https://www.math.wisc.edu/wiki/api.php?action=feedcontributions&user=Jeanluc&feedformat=atomUW-Math Wiki - User contributions [en]2020-03-28T16:22:32ZUser contributionsMediaWiki 1.30.1https://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=19313Applied/Physical Applied Math2020-03-27T09:53:39Z<p>Jeanluc: /* Spring 2020 */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a [https://www.math.wisc.edu/deptmeetings Department Meeting])<br />
*'''Where:''' [https://us.bbcollab.com/guest/0ad27f42c51d4ffbbdff719013f16acd BBCollaborate Ultra] <s>901 Van Vleck Hall</s><br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 30<br />
|Jean-Luc<br />
|Organizational meeting; [https://www.dropbox.com/s/bnjpyud6h8u3lav/homog_periodic_lattice_group_meeting.pdf?dl=0 Homogenization of a periodic lattice]<br />
|-<br />
|Feb. 6<br />
|Gage<br />
|Krasilov et al., [https://bura.brunel.ac.uk/bitstream/2438/419/1/Growing%20Random%20Sequences.pdf Growing random sequences]<br> Makover and McGowan, [https://arxiv.org/abs/math/0510159 An elementary proof that random Fibonacci sequences grow exponentially]<br />
|-<br />
|Feb. 13<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 20<br />
|Saverio<br />
|Greengard and Jiang, [https://epubs.siam.org/doi/abs/10.1137/18M1216158 A New Mixed Potential Representation for Unsteady, Incompressible Flow]<br />
|-<br />
|Feb. 27<br />
|<br />
|''Faculty (EC) Meeting''<br />
|-<br />
|Mar. 5<br />
|Wil<br />
|[https://www.dropbox.com/s/fbidvoslu3twtlv/pam_2020.pdf?dl=0 Implicit surfaces and the closest point problem]<br />
|-<br />
|Mar. 12<br />
|''cancelled''<br />
|<br />
|-<br />
|Mar. 19<br />
|Saverio<br />
|[https://www.dropbox.com/s/h9rmglss07bmyb6/BonusLecture.pdf?dl=0 Primer on SIR models and the epidemic]<br />
|-<br />
|Mar. 26 ''3:30pm''<br />
|Jean-Luc<br />
|[https://youtu.be/B0GNtFApUQ8 Shape Matters: Homogenization for a confined Brownian microswimmer] (seminar at Princeton)<br />
|-<br />
|Apr. 2<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 9<br />
|Ruifu<br />
|Texier, [https://arxiv.org/abs/1907.08512 Fluctuations of the product of random matrices and generalised Lyapunov exponent]<br />
|-<br />
|Apr. 16<br />
|<br />
|<br />
|-<br />
|Apr. 23<br />
|<br />
|<br />
|-<br />
|Apr. 30<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Fall2019|Fall 2019]]<br />
*[[Applied/Physical_Applied_Math/Spring2019|Spring 2019]]<br />
*[[Applied/Physical_Applied_Math/Fall2018|Fall 2018]]<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=19301Applied/Physical Applied Math2020-03-24T14:23:26Z<p>Jeanluc: /* Physical Applied Math Group Meeting */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a [https://www.math.wisc.edu/deptmeetings Department Meeting])<br />
*'''Where:''' [https://us.bbcollab.com/guest/0ad27f42c51d4ffbbdff719013f16acd BBCollaborate Ultra] <s>901 Van Vleck Hall</s><br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 30<br />
|Jean-Luc<br />
|Organizational meeting; [https://www.dropbox.com/s/bnjpyud6h8u3lav/homog_periodic_lattice_group_meeting.pdf?dl=0 Homogenization of a periodic lattice]<br />
|-<br />
|Feb. 6<br />
|Gage<br />
|Krasilov et al., [https://bura.brunel.ac.uk/bitstream/2438/419/1/Growing%20Random%20Sequences.pdf Growing random sequences]<br> Makover and McGowan, [https://arxiv.org/abs/math/0510159 An elementary proof that random Fibonacci sequences grow exponentially]<br />
|-<br />
|Feb. 13<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 20<br />
|Saverio<br />
|Greengard and Jiang, [https://epubs.siam.org/doi/abs/10.1137/18M1216158 A New Mixed Potential Representation for Unsteady, Incompressible Flow]<br />
|-<br />
|Feb. 27<br />
|<br />
|''Faculty (EC) Meeting''<br />
|-<br />
|Mar. 5<br />
|Wil<br />
|[https://www.dropbox.com/s/fbidvoslu3twtlv/pam_2020.pdf?dl=0 Implicit surfaces and the closest point problem]<br />
|-<br />
|Mar. 12<br />
|''cancelled''<br />
|<br />
|-<br />
|Mar. 19<br />
|Saverio<br />
|[https://www.dropbox.com/s/h9rmglss07bmyb6/BonusLecture.pdf?dl=0 Primer on SIR models and the epidemic]<br />
|-<br />
|Mar. 26 ''3:30pm''<br />
|Jean-Luc<br />
|[https://princeton.zoom.us/j/9148065146 Shape Matters: Homogenization for a confined Brownian microswimmer] (seminar at Princeton)<br />
|-<br />
|Apr. 2<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 9<br />
|Ruifu<br />
|Texier, [https://arxiv.org/abs/1907.08512 Fluctuations of the product of random matrices and generalised Lyapunov exponent]<br />
|-<br />
|Apr. 16<br />
|<br />
|<br />
|-<br />
|Apr. 23<br />
|<br />
|<br />
|-<br />
|Apr. 30<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Fall2019|Fall 2019]]<br />
*[[Applied/Physical_Applied_Math/Spring2019|Spring 2019]]<br />
*[[Applied/Physical_Applied_Math/Fall2018|Fall 2018]]<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=19266Applied/Physical Applied Math2020-03-13T14:35:33Z<p>Jeanluc: /* Spring 2020 */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a [https://www.math.wisc.edu/deptmeetings Department Meeting])<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 30<br />
|Jean-Luc<br />
|Organizational meeting; [https://www.dropbox.com/s/bnjpyud6h8u3lav/homog_periodic_lattice_group_meeting.pdf?dl=0 Homogenization of a periodic lattice]<br />
|-<br />
|Feb. 6<br />
|Gage<br />
|Krasilov et al., [https://bura.brunel.ac.uk/bitstream/2438/419/1/Growing%20Random%20Sequences.pdf Growing random sequences]<br> Makover and McGowan, [https://arxiv.org/abs/math/0510159 An elementary proof that random Fibonacci sequences grow exponentially]<br />
|-<br />
|Feb. 13<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 20<br />
|Saverio<br />
|Greengard and Jiang, [https://epubs.siam.org/doi/abs/10.1137/18M1216158 A New Mixed Potential Representation for Unsteady, Incompressible Flow]<br />
|-<br />
|Feb. 27<br />
|<br />
|''Faculty (EC) Meeting''<br />
|-<br />
|Mar. 5<br />
|Wil<br />
|[https://www.dropbox.com/s/fbidvoslu3twtlv/pam_2020.pdf?dl=0 Implicit surfaces and the closest point problem]<br />
|-<br />
|Mar. 12<br />
|Ruifu [''postponed'']<br />
|Texier, [https://arxiv.org/abs/1907.08512 Fluctuations of the product of random matrices and generalised Lyapunov exponent]<br />
|-<br />
|Mar. 19<br />
|<br />
|''Spring Break''<br />
|-<br />
|Mar. 26<br />
|<br />
|<br />
|-<br />
|Apr. 2<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 9<br />
|<br />
|<br />
|-<br />
|Apr. 16<br />
|<br />
|<br />
|-<br />
|Apr. 23<br />
|<br />
|<br />
|-<br />
|Apr. 30<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Fall2019|Fall 2019]]<br />
*[[Applied/Physical_Applied_Math/Spring2019|Spring 2019]]<br />
*[[Applied/Physical_Applied_Math/Fall2018|Fall 2018]]<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=19221Applied/Physical Applied Math2020-03-08T16:00:01Z<p>Jeanluc: /* Spring 2020 */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a [https://www.math.wisc.edu/deptmeetings Department Meeting])<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 30<br />
|Jean-Luc<br />
|Organizational meeting; [https://www.dropbox.com/s/bnjpyud6h8u3lav/homog_periodic_lattice_group_meeting.pdf?dl=0 Homogenization of a periodic lattice]<br />
|-<br />
|Feb. 6<br />
|Gage<br />
|Krasilov et al., [https://bura.brunel.ac.uk/bitstream/2438/419/1/Growing%20Random%20Sequences.pdf Growing random sequences]<br> Makover and McGowan, [https://arxiv.org/abs/math/0510159 An elementary proof that random Fibonacci sequences grow exponentially]<br />
|-<br />
|Feb. 13<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 20<br />
|Saverio<br />
|Greengard and Jiang, [https://epubs.siam.org/doi/abs/10.1137/18M1216158 A New Mixed Potential Representation for Unsteady, Incompressible Flow]<br />
|-<br />
|Feb. 27<br />
|<br />
|''Faculty (EC) Meeting''<br />
|-<br />
|Mar. 5<br />
|Wil<br />
|[https://www.dropbox.com/s/fbidvoslu3twtlv/pam_2020.pdf?dl=0 Implicit surfaces and the closest point problem]<br />
|-<br />
|Mar. 12<br />
|Ruifu<br />
|Texier, [https://arxiv.org/abs/1907.08512 Fluctuations of the product of random matrices and generalised Lyapunov exponent]<br />
|-<br />
|Mar. 19<br />
|<br />
|''Spring Break''<br />
|-<br />
|Mar. 26<br />
|<br />
|<br />
|-<br />
|Apr. 2<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 9<br />
|<br />
|<br />
|-<br />
|Apr. 16<br />
|<br />
|<br />
|-<br />
|Apr. 23<br />
|<br />
|<br />
|-<br />
|Apr. 30<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Fall2019|Fall 2019]]<br />
*[[Applied/Physical_Applied_Math/Spring2019|Spring 2019]]<br />
*[[Applied/Physical_Applied_Math/Fall2018|Fall 2018]]<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=19220Applied/Physical Applied Math2020-03-08T15:47:57Z<p>Jeanluc: /* Spring 2020 */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a [https://www.math.wisc.edu/deptmeetings Department Meeting])<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 30<br />
|Jean-Luc<br />
|Organizational meeting; [https://www.dropbox.com/s/bnjpyud6h8u3lav/homog_periodic_lattice_group_meeting.pdf?dl=0 Homogenization of a periodic lattice]<br />
|-<br />
|Feb. 6<br />
|Gage<br />
|Krasilov et al., [https://bura.brunel.ac.uk/bitstream/2438/419/1/Growing%20Random%20Sequences.pdf Growing random sequences]<br> Makover and McGowan, [https://arxiv.org/abs/math/0510159 An elementary proof that random Fibonacci sequences grow exponentially]<br />
|-<br />
|Feb. 13<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 20<br />
|Saverio<br />
|Greengard and Jiang, [https://epubs.siam.org/doi/abs/10.1137/18M1216158 A New Mixed Potential Representation for Unsteady, Incompressible Flow]<br />
|-<br />
|Feb. 27<br />
|<br />
|''Faculty (EC) Meeting''<br />
|-<br />
|Mar. 5<br />
|Wil<br />
|[https://www.dropbox.com/s/fbidvoslu3twtlv/pam_2020.pdf?dl=0 Implicit surfaces and the closest point problem]<br />
|-<br />
|Mar. 12<br />
|<br />
|''no meeting this week''<br />
|-<br />
|Mar. 19<br />
|<br />
|''Spring Break''<br />
|-<br />
|Mar. 26<br />
|Ruifu<br />
|<br />
|-<br />
|Apr. 2<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 9<br />
|<br />
|<br />
|-<br />
|Apr. 16<br />
|<br />
|<br />
|-<br />
|Apr. 23<br />
|<br />
|<br />
|-<br />
|Apr. 30<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Fall2019|Fall 2019]]<br />
*[[Applied/Physical_Applied_Math/Spring2019|Spring 2019]]<br />
*[[Applied/Physical_Applied_Math/Fall2018|Fall 2018]]<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=19207Applied/Physical Applied Math2020-03-05T17:36:08Z<p>Jeanluc: /* Spring 2020 */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a [https://www.math.wisc.edu/deptmeetings Department Meeting])<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 30<br />
|Jean-Luc<br />
|Organizational meeting; [https://www.dropbox.com/s/bnjpyud6h8u3lav/homog_periodic_lattice_group_meeting.pdf?dl=0 Homogenization of a periodic lattice]<br />
|-<br />
|Feb. 6<br />
|Gage<br />
|Krasilov et al., [https://bura.brunel.ac.uk/bitstream/2438/419/1/Growing%20Random%20Sequences.pdf Growing random sequences]<br> Makover and McGowan, [https://arxiv.org/abs/math/0510159 An elementary proof that random Fibonacci sequences grow exponentially]<br />
|-<br />
|Feb. 13<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 20<br />
|Saverio<br />
|Greengard and Jiang, [https://epubs.siam.org/doi/abs/10.1137/18M1216158 A New Mixed Potential Representation for Unsteady, Incompressible Flow]<br />
|-<br />
|Feb. 27<br />
|<br />
|''Faculty (EC) Meeting''<br />
|-<br />
|Mar. 5<br />
|Wil<br />
|[https://www.dropbox.com/s/fbidvoslu3twtlv/pam_2020.pdf?dl=0 Implicit surfaces and the closest point problem]<br />
|-<br />
|Mar. 12<br />
|Ruifu<br />
|<br />
|-<br />
|Mar. 19<br />
|<br />
|''Spring Break''<br />
|-<br />
|Mar. 26<br />
|<br />
|<br />
|-<br />
|Apr. 2<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 9<br />
|<br />
|<br />
|-<br />
|Apr. 16<br />
|<br />
|<br />
|-<br />
|Apr. 23<br />
|<br />
|<br />
|-<br />
|Apr. 30<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Fall2019|Fall 2019]]<br />
*[[Applied/Physical_Applied_Math/Spring2019|Spring 2019]]<br />
*[[Applied/Physical_Applied_Math/Fall2018|Fall 2018]]<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=19188Applied/Physical Applied Math2020-03-04T07:15:21Z<p>Jeanluc: /* Spring 2020 */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a [https://www.math.wisc.edu/deptmeetings Department Meeting])<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 30<br />
|Jean-Luc<br />
|Organizational meeting; [https://www.dropbox.com/s/bnjpyud6h8u3lav/homog_periodic_lattice_group_meeting.pdf?dl=0 Homogenization of a periodic lattice]<br />
|-<br />
|Feb. 6<br />
|Gage<br />
|Krasilov et al., [https://bura.brunel.ac.uk/bitstream/2438/419/1/Growing%20Random%20Sequences.pdf Growing random sequences]<br> Makover and McGowan, [https://arxiv.org/abs/math/0510159 An elementary proof that random Fibonacci sequences grow exponentially]<br />
|-<br />
|Feb. 13<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 20<br />
|Saverio<br />
|Greengard and Jiang, [https://epubs.siam.org/doi/abs/10.1137/18M1216158 A New Mixed Potential Representation for Unsteady, Incompressible Flow]<br />
|-<br />
|Feb. 27<br />
|<br />
|''Faculty (EC) Meeting''<br />
|-<br />
|Mar. 5<br />
|Wil<br />
|[https://www.dropbox.com/s/fbidvoslu3twtlv/pam_2020.pdf?dl=0 Implicit surfaces and the closest point problem]<br />
|-<br />
|Mar. 12<br />
|Ruifu<br />
|''EC?''<br />
|-<br />
|Mar. 19<br />
|<br />
|''Spring Break''<br />
|-<br />
|Mar. 26<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 2<br />
|Keaton Burns?<br />
|<br />
|-<br />
|Apr. 9<br />
|<br />
|<br />
|-<br />
|Apr. 16<br />
|<br />
|<br />
|-<br />
|Apr. 23<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 30<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Fall2019|Fall 2019]]<br />
*[[Applied/Physical_Applied_Math/Spring2019|Spring 2019]]<br />
*[[Applied/Physical_Applied_Math/Fall2018|Fall 2018]]<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=19129Applied/Physical Applied Math2020-02-25T15:30:50Z<p>Jeanluc: /* Spring 2020 */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a [https://www.math.wisc.edu/deptmeetings Department Meeting])<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 30<br />
|Jean-Luc<br />
|Organizational meeting; [https://www.dropbox.com/s/bnjpyud6h8u3lav/homog_periodic_lattice_group_meeting.pdf?dl=0 Homogenization of a periodic lattice]<br />
|-<br />
|Feb. 6<br />
|Gage<br />
|Krasilov et al., [https://bura.brunel.ac.uk/bitstream/2438/419/1/Growing%20Random%20Sequences.pdf Growing random sequences]<br> Makover and McGowan, [https://arxiv.org/abs/math/0510159 An elementary proof that random Fibonacci sequences grow exponentially]<br />
|-<br />
|Feb. 13<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 20<br />
|Saverio<br />
|Greengard and Jiang, [https://epubs.siam.org/doi/abs/10.1137/18M1216158 A New Mixed Potential Representation for Unsteady, Incompressible Flow]<br />
|-<br />
|Feb. 27<br />
|<br />
|''Faculty (EC) Meeting''<br />
|-<br />
|Mar. 5<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Mar. 12<br />
|Ruifu<br />
|''EC?''<br />
|-<br />
|Mar. 19<br />
|<br />
|''Spring Break''<br />
|-<br />
|Mar. 26<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 2<br />
|Keaton Burns?<br />
|<br />
|-<br />
|Apr. 9<br />
|<br />
|<br />
|-<br />
|Apr. 16<br />
|<br />
|<br />
|-<br />
|Apr. 23<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 30<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Fall2019|Fall 2019]]<br />
*[[Applied/Physical_Applied_Math/Spring2019|Spring 2019]]<br />
*[[Applied/Physical_Applied_Math/Fall2018|Fall 2018]]<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Colloquia&diff=18998Colloquia2020-02-11T16:04:41Z<p>Jeanluc: /* Mathematics Colloquium */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Mathematics Colloquium =<br />
<br />
All colloquia are on Fridays at 4:00 pm in Van Vleck B239, '''unless otherwise indicated'''.<br />
<br />
<br />
<br />
==Spring 2020==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|<br />
|-<br />
|Jan 10<br />
|Thomas Lam (Michigan) <br />
|[[#Thomas Lam (Michigan) |Positive geometries and string theory amplitudes]]<br />
|Erman<br />
|-<br />
|Jan 21 '''Tuesday 4-5 pm in B139'''<br />
|[http://www.nd.edu/~cholak/ Peter Cholak] (Notre Dame) <br />
|[[#Peter Cholak (Notre Dame) |What can we compute from solutions to combinatorial problems?]]<br />
|Lempp<br />
|-<br />
|Jan 24<br />
|[https://math.duke.edu/people/saulo-orizaga Saulo Orizaga] (Duke)<br />
|[[#Saulo Orizaga (Duke) | Introduction to phase field models and their efficient numerical implementation ]]<br />
|<br />
|-<br />
|Jan 27 '''Monday 4-5 pm in 911'''<br />
|[https://math.yale.edu/people/caglar-uyanik Caglar Uyanik] (Yale)<br />
|[[#Caglar Uyanik (Yale) | Hausdorff dimension and gap distribution in billiards ]]<br />
|Ellenberg<br />
|-<br />
|Jan 29 '''Wednesday 4-5 pm'''<br />
|[https://ajzucker.wordpress.com/ Andy Zucker] (Lyon)<br />
|[[#Andy Zucker (Lyon) |Topological dynamics of countable groups and structures]]<br />
|Soskova/Lempp<br />
|-<br />
|Jan 31 <br />
|[https://services.math.duke.edu/~pierce/ Lillian Pierce] (Duke)<br />
|[[#Lillian Pierce (Duke) |On Bourgain’s counterexample for the Schrödinger maximal function]]<br />
|Marshall/Seeger<br />
|-<br />
|Feb 7<br />
|[https://web.math.princeton.edu/~jkileel/ Joe Kileel] (Princeton)<br />
|[[#Joe Kileel (Princeton) |Inverse Problems, Imaging and Tensor Decomposition]]<br />
|Roch<br />
|-<br />
|Feb 10<br />
|[https://clvinzan.math.ncsu.edu/ Cynthia Vinzant] (NCSU)<br />
|[[#Cynthia Vinzant (NCSU) |Matroids, log-concavity, and expanders]]<br />
|Roch/Erman<br />
|-<br />
|Feb 12 '''Wednesday 4-5 pm in VV 911'''<br />
|[https://www.machuang.org/ Jinzi Mac Huang] (UCSD)<br />
|[[#Jinzi Mac Huang (UCSD) |Mass transfer through fluid-structure interactions]]<br />
|Spagnolie<br />
|-<br />
|Feb 14<br />
|[https://math.unt.edu/people/william-chan/ William Chan] (University of North Texas)<br />
|[[#William Chan (University of North Texas) |Definable infinitary combinatorics under determinacy]]<br />
|Soskova/Lempp<br />
|-<br />
|Feb 17<br />
|[https://yisun.io/ Yi Sun] (Columbia)<br />
|[[#Yi Sun (Columbia) |Fluctuations for products of random matrices]]<br />
|Roch<br />
|-<br />
|Feb 19<br />
|[https://www.math.upenn.edu/~zwang423// Zhenfu Wang] (University of Pennsylvania)<br />
|[[#Zhenfu Wang (University of Pennsylvania) |Quantitative Methods for the Mean Field Limit Problem]]<br />
|Tran<br />
|-<br />
|Feb 21<br />
|Shai Evra (IAS)<br />
|<br />
|Gurevich<br />
|<br />
|-<br />
|Feb 28<br />
|Brett Wick (Washington University, St. Louis)<br />
|<br />
|Seeger<br />
|-<br />
|March 6<br />
| Jessica Fintzen (Michigan)<br />
|<br />
|Marshall<br />
|-<br />
|March 13<br />
|<br />
|-<br />
|March 20<br />
|Spring break<br />
|<br />
|-<br />
|March 27<br />
|[https://max.lieblich.us/ Max Lieblich] (Univ. of Washington, Seattle)<br />
|<br />
|Boggess, Sankar<br />
|-<br />
|April 3<br />
|Caroline Turnage-Butterbaugh (Carleton College)<br />
|<br />
|Marshall<br />
|-<br />
|April 10<br />
| Sarah Koch (Michigan)<br />
|<br />
| Bruce (WIMAW)<br />
|-<br />
|April 17<br />
|JM Landsberg (TAMU)<br />
|TBA<br />
|Gurevich<br />
|-<br />
|April 23<br />
|Martin Hairer (Imperial College London)<br />
|Wolfgang Wasow Lecture<br />
|Hao Shen<br />
|-<br />
|April 24<br />
|Natasa Sesum (Rutgers University)<br />
|<br />
|Angenent<br />
|-<br />
|May 1<br />
|Robert Lazarsfeld (Stony Brook)<br />
|Distinguished lecture<br />
|Erman<br />
|}<br />
<br />
<br />
== Abstracts ==<br />
<br />
=== Thomas Lam (Michigan) === <br />
<br />
Title: Positive geometries and string theory amplitudes<br />
<br />
Abstract: Inspired by developments in quantum field theory, we<br />
recently defined the notion of a positive geometry, a class of spaces<br />
that includes convex polytopes, positive parts of projective toric<br />
varieties, and positive parts of flag varieties. I will discuss some<br />
basic features of the theory and an application to genus zero string<br />
theory amplitudes. As a special case, we obtain the Euler beta<br />
function, familiar to mathematicians, as the "stringy canonical form"<br />
of the closed interval.<br />
<br />
This talk is based on joint work with Arkani-Hamed, Bai, and He.<br />
<br />
=== Peter Cholak (Notre Dame) ===<br />
<br />
Title: What can we compute from solutions to combinatorial problems?<br />
<br />
Abstract: This will be an introductory talk to an exciting current <br />
research area in mathematical logic. Mostly we are interested in <br />
solutions to Ramsey's Theorem. Ramsey's Theorem says for colorings <br />
C of pairs of natural numbers, there is an infinite set H such that <br />
all pairs from H have the same constant color. H is called a homogeneous <br />
set for C. What can we compute from H? If you are not sure, come to <br />
the talk and find out!<br />
<br />
=== Saulo Orizaga (Duke) ===<br />
<br />
Title: Introduction to phase field models and their efficient numerical implementation<br />
<br />
Abstract: In this talk we will provide an introduction to phase field models. We will focus in models<br />
related to the Cahn-Hilliard (CH) type of partial differential equation (PDE). We will discuss the<br />
challenges associated in solving such higher order parabolic problems. We will present several<br />
new numerical methods that are fast and efficient for solving CH or CH-extended type of problems.<br />
The new methods and their energy-stability properties will be discussed and tested with several computational examples commonly found in material science problems. If time allows, we will talk about more applications in which phase field models are useful and applicable.<br />
<br />
=== Caglar Uyanik (Yale) ===<br />
<br />
Title: Hausdorff dimension and gap distribution in billiards<br />
<br />
Abstract: A classical “unfolding” procedure allows one to turn questions about billiard trajectories in a Euclidean polygon into questions about the geodesic flow on a surface equipped with a certain geometric structure. Surprisingly, the flow on the surface is in turn related to the geodesic flow on the classical moduli spaces of Riemann surfaces. Building on recent breakthrough results of Eskin-Mirzakhani-Mohammadi, we prove a large deviations result for Birkhoff averages as well as generalize a classical theorem of Masur on geodesics in the moduli spaces of translation surfaces. <br />
<br />
=== Andy Zucker (Lyon) ===<br />
<br />
Title: Topological dynamics of countable groups and structures<br />
<br />
Abstract: We give an introduction to the abstract topological dynamics <br />
of topological groups, i.e. the study of the continuous actions of a <br />
topological group on a compact space. We are particularly interested <br />
in the minimal actions, those for which every orbit is dense. <br />
The study of minimal actions is aided by a classical theorem of Ellis, <br />
who proved that for any topological group G, there exists a universal <br />
minimal flow (UMF), a minimal G-action which factors onto every other <br />
minimal G-action. Here, we will focus on two classes of groups: <br />
a countable discrete group and the automorphism group of a countable <br />
first-order structure. In the case of a countable discrete group, <br />
Baire category methods can be used to show that the collection of <br />
minimal flows is quite rich and that the UMF is rather complicated. <br />
For an automorphism group G of a countable structure, combinatorial <br />
methods can be used to show that sometimes, the UMF is trivial, or <br />
equivalently that every continuous action of G on a compact space <br />
admits a global fixed point.<br />
<br />
=== Lillian Pierce (Duke) ===<br />
<br />
Title: On Bourgain’s counterexample for the Schrödinger maximal function<br />
<br />
Abstract: In 1980, Carleson asked a question in harmonic analysis: to which Sobolev space $H^s$ must an initial data function belong, for a pointwise a.e. convergence result to hold for the solution to the associated linear Schrödinger equation? Over the next decades, many people developed counterexamples to push the (necessary) range of s up, and positive results to push the (sufficient) range of s down. Now, these ranges are finally meeting: Bourgain’s 2016 counterexample showed s < n/(2(n+1)) fails, and Du and Zhang’s 2019 paper shows that s>n/(2(n+1)) suffices. <br />
In this talk, we will give an overview of how to rigorously derive Bourgain’s 2016 counterexample, based on simple facts from number theory. We will show how to build Bourgain’s counterexample starting from “zero knowledge," and how to gradually optimize the set-up to arrive at the final counterexample. The talk will be broadly accessible, particularly if we live up to the claim of starting from “zero knowledge.”<br />
<br />
=== Joe Kileel (Princeton) ===<br />
<br />
Title: Inverse Problems, Imaging and Tensor Decomposition<br />
<br />
Abstract: Perspectives from computational algebra and optimization are brought <br />
to bear on a scientific application and a data science application. <br />
In the first part of the talk, I will discuss cryo-electron microscopy <br />
(cryo-EM), an imaging technique to determine the 3-D shape of <br />
macromolecules from many noisy 2-D projections, recognized by the 2017 <br />
Chemistry Nobel Prize. Mathematically, cryo-EM presents a <br />
particularly rich inverse problem, with unknown orientations, extreme <br />
noise, big data and conformational heterogeneity. In particular, this <br />
motivates a general framework for statistical estimation under compact <br />
group actions, connecting information theory and group invariant <br />
theory. In the second part of the talk, I will discuss tensor rank <br />
decomposition, a higher-order variant of PCA broadly applicable in <br />
data science. A fast algorithm is introduced and analyzed, combining <br />
ideas of Sylvester and the power method.<br />
<br />
=== Cynthia Vinzant (NCSU) ===<br />
<br />
Title: Matroids, log-concavity, and expanders<br />
<br />
Abstract: Matroids are combinatorial objects that model various types of independence. They appear several fields mathematics, including graph theory, combinatorial optimization, and algebraic geometry. In this talk, I will introduce the theory of matroids along with the closely related class of polynomials called strongly log-concave polynomials. Strong log-concavity is a functional property of a real multivariate polynomial that translates to useful conditions on its coefficients. Discrete probability distributions defined by these coefficients inherit several of these nice properties. I will discuss the beautiful real and combinatorial geometry underlying these polynomials and describe applications to random walks on the faces of simplicial complexes. Consequences include proofs of Mason's conjecture that the sequence of numbers of independent sets of a matroid is ultra log-concave and the Mihail-Vazirani conjecture that the basis exchange graph of a matroid has expansion at least one. This is based on joint work with Nima Anari, Kuikui Liu, and Shayan Oveis Gharan.<br />
<br />
=== Jinzi Mac Huang (UCSD) ===<br />
<br />
Title: Mass transfer through fluid-structure interactions<br />
<br />
Abstract: The advancement of mathematics is closely associated with new discoveries from physical experiments. On one hand, mathematical tools like numerical simulation can help explain observations from experiments. On the other hand, experimental discoveries of physical phenomena, such as Brownian motion, can inspire the development of new mathematical approaches. In this talk, we focus on the interplay between applied math and experiments involving fluid-structure interactions -- a fascinating topic with both physical relevance and mathematical complexity. One such problem, inspired by geophysical fluid dynamics, is the experimental and numerical study of the dissolution of solid bodies in a fluid flow. The results of this study allow us to sketch mathematical answers to some long standing questions like the formation of stone forests in China and Madagascar, and how many licks it takes to get to the center of a Tootsie Pop. We will also talk about experimental math problems at the micro-scale, focusing on the mass transport process of diffusiophoresis, where colloidal particles are advected by a concentration gradient of salt solution. Exploiting this phenomenon, we see that colloids are able to navigate a micro-maze that has a salt concentration gradient across the exit and entry points. We further demonstrate that their ability to solve the maze is closely associated with the properties of a harmonic function – the salt concentration.<br />
<br />
=== William Chan (University of North Texas) ===<br />
<br />
Title: Definable infinitary combinatorics under determinacy<br />
<br />
Abstract: The axiom of determinacy, AD, states that in any infinite two player integer game of a certain form, one of the two players must have a winning strategy. It is incompatible with the ZFC set theory axioms with choice; however, it is a succinct extension of ZF which implies many subsets of the real line possess familiar regularity properties and eliminates many pathological sets. For instance, AD implies all sets of reals are Lebesgue measurable and every function from the reals to the reals is continuous on a comeager set. Determinacy also implies that the first uncountable cardinal has the strong partition property which can be used to define the partition measures. This talk will give an overview of the axiom of determinacy and will discuss recent results on the infinitary combinatorics surrounding the first uncountable cardinal and its partition measures. I will discuss the almost everywhere continuity phenomenon for functions outputting countable ordinals and the almost-everywhere uniformization results for closed and unbounded subsets of the first uncountable cardinal. These will be used to describe the rich structure of the cardinals below the powerset of the first and second uncountable cardinals under determinacy assumptions and to investigate the ultrapowers by these partition measures.<br />
<br />
=== Yi Sun (Columbia) ===<br />
<br />
Title: Fluctuations for products of random matrices<br />
<br />
Abstract: Products of large random matrices appear in many modern applications such as high dimensional statistics (MANOVA estimators), machine learning (Jacobians of neural networks), and population ecology (transition matrices of dynamical systems). Inspired by these situations, this talk concerns global limits and fluctuations of singular values of products of independent random matrices as both the size N and number M of matrices grow. As N grows, I will show for a variety of ensembles that fluctuations of the Lyapunov exponents converge to explicit Gaussian fields which transition from log-correlated for fixed M to having a white noise component for M growing with N. I will sketch our method, which uses multivariate generalizations of the Laplace transform based on the multivariate Bessel function from representation theory.<br />
<br />
=== Zhenfu Wang (University of Pennsylvania) ===<br />
<br />
Title: Quantitative Methods for the Mean Field Limit Problem<br />
<br />
Abstract: We study the mean field limit of large systems of interacting particles. Classical mean field limit results require that the interaction kernels be essentially Lipschitz. To handle more singular interaction kernels is a longstanding and challenging question but which now has some successes. Joint with P.-E. Jabin, we use the relative entropy between the joint law of all particles and the tensorized law at the limit to quantify the convergence from the particle systems towards the macroscopic PDEs. This method requires to prove large deviations estimates for non-continuous potentials modified by the limiting law. But it leads to explicit convergence rates for all marginals. This in particular can be applied to the Biot-Savart law for 2D Navier-Stokes. To treat more general and singular kernels, joint with D. Bresch and P.-E. Jabin, we introduce the modulated free energy, combination of the relative entropy that we had previously developed and of the modulated energy introduced by S. Serfaty. This modulated free energy may be understood as introducing appropriate weights in the relative entropy to cancel the most singular terms involving the divergence of the kernels. Our modulated free energy allows to treat gradient flows with singular potentials which combine large smooth part, small attractive singular part and large repulsive singular part. As an example, a full rigorous derivation (with quantitative estimates) of some chemotaxis models, such as the Patlak-Keller-Segel system in the subcritical regimes, is obtained.<br />
<br />
== Future Colloquia ==<br />
[[Colloquia/Fall 2020| Fall 2020]]<br />
<br />
== Past Colloquia ==<br />
<br />
[[Colloquia/Fall2019|Fall 2019]]<br />
<br />
[[Colloquia/Spring2019|Spring 2019]]<br />
<br />
[[Colloquia/Fall2018|Fall 2018]]<br />
<br />
[[Colloquia/Spring2018|Spring 2018]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Colloquia&diff=18997Colloquia2020-02-11T16:03:41Z<p>Jeanluc: Move Fall 2019 to archived page.</p>
<hr />
<div>= Mathematics Colloquium =<br />
<br />
All colloquia are on Fridays at 4:00 pm in Van Vleck B239, '''unless otherwise indicated'''.<br />
<br />
<br />
<br />
==Spring 2020==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|<br />
|-<br />
|Jan 10<br />
|Thomas Lam (Michigan) <br />
|[[#Thomas Lam (Michigan) |Positive geometries and string theory amplitudes]]<br />
|Erman<br />
|-<br />
|Jan 21 '''Tuesday 4-5 pm in B139'''<br />
|[http://www.nd.edu/~cholak/ Peter Cholak] (Notre Dame) <br />
|[[#Peter Cholak (Notre Dame) |What can we compute from solutions to combinatorial problems?]]<br />
|Lempp<br />
|-<br />
|Jan 24<br />
|[https://math.duke.edu/people/saulo-orizaga Saulo Orizaga] (Duke)<br />
|[[#Saulo Orizaga (Duke) | Introduction to phase field models and their efficient numerical implementation ]]<br />
|<br />
|-<br />
|Jan 27 '''Monday 4-5 pm in 911'''<br />
|[https://math.yale.edu/people/caglar-uyanik Caglar Uyanik] (Yale)<br />
|[[#Caglar Uyanik (Yale) | Hausdorff dimension and gap distribution in billiards ]]<br />
|Ellenberg<br />
|-<br />
|Jan 29 '''Wednesday 4-5 pm'''<br />
|[https://ajzucker.wordpress.com/ Andy Zucker] (Lyon)<br />
|[[#Andy Zucker (Lyon) |Topological dynamics of countable groups and structures]]<br />
|Soskova/Lempp<br />
|-<br />
|Jan 31 <br />
|[https://services.math.duke.edu/~pierce/ Lillian Pierce] (Duke)<br />
|[[#Lillian Pierce (Duke) |On Bourgain’s counterexample for the Schrödinger maximal function]]<br />
|Marshall/Seeger<br />
|-<br />
|Feb 7<br />
|[https://web.math.princeton.edu/~jkileel/ Joe Kileel] (Princeton)<br />
|[[#Joe Kileel (Princeton) |Inverse Problems, Imaging and Tensor Decomposition]]<br />
|Roch<br />
|-<br />
|Feb 10<br />
|[https://clvinzan.math.ncsu.edu/ Cynthia Vinzant] (NCSU)<br />
|[[#Cynthia Vinzant (NCSU) |Matroids, log-concavity, and expanders]]<br />
|Roch/Erman<br />
|-<br />
|Feb 12 '''Wednesday 4-5 pm in VV 911'''<br />
|[https://www.machuang.org/ Jinzi Mac Huang] (UCSD)<br />
|[[#Jinzi Mac Huang (UCSD) |Mass transfer through fluid-structure interactions]]<br />
|Spagnolie<br />
|-<br />
|Feb 14<br />
|[https://math.unt.edu/people/william-chan/ William Chan] (University of North Texas)<br />
|[[#William Chan (University of North Texas) |Definable infinitary combinatorics under determinacy]]<br />
|Soskova/Lempp<br />
|-<br />
|Feb 17<br />
|[https://yisun.io/ Yi Sun] (Columbia)<br />
|[[#Yi Sun (Columbia) |Fluctuations for products of random matrices]]<br />
|Roch<br />
|-<br />
|Feb 19<br />
|[https://www.math.upenn.edu/~zwang423// Zhenfu Wang] (University of Pennsylvania)<br />
|[[#Zhenfu Wang (University of Pennsylvania) |Quantitative Methods for the Mean Field Limit Problem]]<br />
|Tran<br />
|-<br />
|Feb 21<br />
|Shai Evra (IAS)<br />
|<br />
|Gurevich<br />
|<br />
|-<br />
|Feb 28<br />
|Brett Wick (Washington University, St. Louis)<br />
|<br />
|Seeger<br />
|-<br />
|March 6<br />
| Jessica Fintzen (Michigan)<br />
|<br />
|Marshall<br />
|-<br />
|March 13<br />
|<br />
|-<br />
|March 20<br />
|Spring break<br />
|<br />
|-<br />
|March 27<br />
|[https://max.lieblich.us/ Max Lieblich] (Univ. of Washington, Seattle)<br />
|<br />
|Boggess, Sankar<br />
|-<br />
|April 3<br />
|Caroline Turnage-Butterbaugh (Carleton College)<br />
|<br />
|Marshall<br />
|-<br />
|April 10<br />
| Sarah Koch (Michigan)<br />
|<br />
| Bruce (WIMAW)<br />
|-<br />
|April 17<br />
|JM Landsberg (TAMU)<br />
|TBA<br />
|Gurevich<br />
|-<br />
|April 23<br />
|Martin Hairer (Imperial College London)<br />
|Wolfgang Wasow Lecture<br />
|Hao Shen<br />
|-<br />
|April 24<br />
|Natasa Sesum (Rutgers University)<br />
|<br />
|Angenent<br />
|-<br />
|May 1<br />
|Robert Lazarsfeld (Stony Brook)<br />
|Distinguished lecture<br />
|Erman<br />
|}<br />
<br />
<br />
== Abstracts ==<br />
<br />
=== Thomas Lam (Michigan) === <br />
<br />
Title: Positive geometries and string theory amplitudes<br />
<br />
Abstract: Inspired by developments in quantum field theory, we<br />
recently defined the notion of a positive geometry, a class of spaces<br />
that includes convex polytopes, positive parts of projective toric<br />
varieties, and positive parts of flag varieties. I will discuss some<br />
basic features of the theory and an application to genus zero string<br />
theory amplitudes. As a special case, we obtain the Euler beta<br />
function, familiar to mathematicians, as the "stringy canonical form"<br />
of the closed interval.<br />
<br />
This talk is based on joint work with Arkani-Hamed, Bai, and He.<br />
<br />
=== Peter Cholak (Notre Dame) ===<br />
<br />
Title: What can we compute from solutions to combinatorial problems?<br />
<br />
Abstract: This will be an introductory talk to an exciting current <br />
research area in mathematical logic. Mostly we are interested in <br />
solutions to Ramsey's Theorem. Ramsey's Theorem says for colorings <br />
C of pairs of natural numbers, there is an infinite set H such that <br />
all pairs from H have the same constant color. H is called a homogeneous <br />
set for C. What can we compute from H? If you are not sure, come to <br />
the talk and find out!<br />
<br />
=== Saulo Orizaga (Duke) ===<br />
<br />
Title: Introduction to phase field models and their efficient numerical implementation<br />
<br />
Abstract: In this talk we will provide an introduction to phase field models. We will focus in models<br />
related to the Cahn-Hilliard (CH) type of partial differential equation (PDE). We will discuss the<br />
challenges associated in solving such higher order parabolic problems. We will present several<br />
new numerical methods that are fast and efficient for solving CH or CH-extended type of problems.<br />
The new methods and their energy-stability properties will be discussed and tested with several computational examples commonly found in material science problems. If time allows, we will talk about more applications in which phase field models are useful and applicable.<br />
<br />
=== Caglar Uyanik (Yale) ===<br />
<br />
Title: Hausdorff dimension and gap distribution in billiards<br />
<br />
Abstract: A classical “unfolding” procedure allows one to turn questions about billiard trajectories in a Euclidean polygon into questions about the geodesic flow on a surface equipped with a certain geometric structure. Surprisingly, the flow on the surface is in turn related to the geodesic flow on the classical moduli spaces of Riemann surfaces. Building on recent breakthrough results of Eskin-Mirzakhani-Mohammadi, we prove a large deviations result for Birkhoff averages as well as generalize a classical theorem of Masur on geodesics in the moduli spaces of translation surfaces. <br />
<br />
=== Andy Zucker (Lyon) ===<br />
<br />
Title: Topological dynamics of countable groups and structures<br />
<br />
Abstract: We give an introduction to the abstract topological dynamics <br />
of topological groups, i.e. the study of the continuous actions of a <br />
topological group on a compact space. We are particularly interested <br />
in the minimal actions, those for which every orbit is dense. <br />
The study of minimal actions is aided by a classical theorem of Ellis, <br />
who proved that for any topological group G, there exists a universal <br />
minimal flow (UMF), a minimal G-action which factors onto every other <br />
minimal G-action. Here, we will focus on two classes of groups: <br />
a countable discrete group and the automorphism group of a countable <br />
first-order structure. In the case of a countable discrete group, <br />
Baire category methods can be used to show that the collection of <br />
minimal flows is quite rich and that the UMF is rather complicated. <br />
For an automorphism group G of a countable structure, combinatorial <br />
methods can be used to show that sometimes, the UMF is trivial, or <br />
equivalently that every continuous action of G on a compact space <br />
admits a global fixed point.<br />
<br />
=== Lillian Pierce (Duke) ===<br />
<br />
Title: On Bourgain’s counterexample for the Schrödinger maximal function<br />
<br />
Abstract: In 1980, Carleson asked a question in harmonic analysis: to which Sobolev space $H^s$ must an initial data function belong, for a pointwise a.e. convergence result to hold for the solution to the associated linear Schrödinger equation? Over the next decades, many people developed counterexamples to push the (necessary) range of s up, and positive results to push the (sufficient) range of s down. Now, these ranges are finally meeting: Bourgain’s 2016 counterexample showed s < n/(2(n+1)) fails, and Du and Zhang’s 2019 paper shows that s>n/(2(n+1)) suffices. <br />
In this talk, we will give an overview of how to rigorously derive Bourgain’s 2016 counterexample, based on simple facts from number theory. We will show how to build Bourgain’s counterexample starting from “zero knowledge," and how to gradually optimize the set-up to arrive at the final counterexample. The talk will be broadly accessible, particularly if we live up to the claim of starting from “zero knowledge.”<br />
<br />
=== Joe Kileel (Princeton) ===<br />
<br />
Title: Inverse Problems, Imaging and Tensor Decomposition<br />
<br />
Abstract: Perspectives from computational algebra and optimization are brought <br />
to bear on a scientific application and a data science application. <br />
In the first part of the talk, I will discuss cryo-electron microscopy <br />
(cryo-EM), an imaging technique to determine the 3-D shape of <br />
macromolecules from many noisy 2-D projections, recognized by the 2017 <br />
Chemistry Nobel Prize. Mathematically, cryo-EM presents a <br />
particularly rich inverse problem, with unknown orientations, extreme <br />
noise, big data and conformational heterogeneity. In particular, this <br />
motivates a general framework for statistical estimation under compact <br />
group actions, connecting information theory and group invariant <br />
theory. In the second part of the talk, I will discuss tensor rank <br />
decomposition, a higher-order variant of PCA broadly applicable in <br />
data science. A fast algorithm is introduced and analyzed, combining <br />
ideas of Sylvester and the power method.<br />
<br />
=== Cynthia Vinzant (NCSU) ===<br />
<br />
Title: Matroids, log-concavity, and expanders<br />
<br />
Abstract: Matroids are combinatorial objects that model various types of independence. They appear several fields mathematics, including graph theory, combinatorial optimization, and algebraic geometry. In this talk, I will introduce the theory of matroids along with the closely related class of polynomials called strongly log-concave polynomials. Strong log-concavity is a functional property of a real multivariate polynomial that translates to useful conditions on its coefficients. Discrete probability distributions defined by these coefficients inherit several of these nice properties. I will discuss the beautiful real and combinatorial geometry underlying these polynomials and describe applications to random walks on the faces of simplicial complexes. Consequences include proofs of Mason's conjecture that the sequence of numbers of independent sets of a matroid is ultra log-concave and the Mihail-Vazirani conjecture that the basis exchange graph of a matroid has expansion at least one. This is based on joint work with Nima Anari, Kuikui Liu, and Shayan Oveis Gharan.<br />
<br />
=== Jinzi Mac Huang (UCSD) ===<br />
<br />
Title: Mass transfer through fluid-structure interactions<br />
<br />
Abstract: The advancement of mathematics is closely associated with new discoveries from physical experiments. On one hand, mathematical tools like numerical simulation can help explain observations from experiments. On the other hand, experimental discoveries of physical phenomena, such as Brownian motion, can inspire the development of new mathematical approaches. In this talk, we focus on the interplay between applied math and experiments involving fluid-structure interactions -- a fascinating topic with both physical relevance and mathematical complexity. One such problem, inspired by geophysical fluid dynamics, is the experimental and numerical study of the dissolution of solid bodies in a fluid flow. The results of this study allow us to sketch mathematical answers to some long standing questions like the formation of stone forests in China and Madagascar, and how many licks it takes to get to the center of a Tootsie Pop. We will also talk about experimental math problems at the micro-scale, focusing on the mass transport process of diffusiophoresis, where colloidal particles are advected by a concentration gradient of salt solution. Exploiting this phenomenon, we see that colloids are able to navigate a micro-maze that has a salt concentration gradient across the exit and entry points. We further demonstrate that their ability to solve the maze is closely associated with the properties of a harmonic function – the salt concentration.<br />
<br />
=== William Chan (University of North Texas) ===<br />
<br />
Title: Definable infinitary combinatorics under determinacy<br />
<br />
Abstract: The axiom of determinacy, AD, states that in any infinite two player integer game of a certain form, one of the two players must have a winning strategy. It is incompatible with the ZFC set theory axioms with choice; however, it is a succinct extension of ZF which implies many subsets of the real line possess familiar regularity properties and eliminates many pathological sets. For instance, AD implies all sets of reals are Lebesgue measurable and every function from the reals to the reals is continuous on a comeager set. Determinacy also implies that the first uncountable cardinal has the strong partition property which can be used to define the partition measures. This talk will give an overview of the axiom of determinacy and will discuss recent results on the infinitary combinatorics surrounding the first uncountable cardinal and its partition measures. I will discuss the almost everywhere continuity phenomenon for functions outputting countable ordinals and the almost-everywhere uniformization results for closed and unbounded subsets of the first uncountable cardinal. These will be used to describe the rich structure of the cardinals below the powerset of the first and second uncountable cardinals under determinacy assumptions and to investigate the ultrapowers by these partition measures.<br />
<br />
=== Yi Sun (Columbia) ===<br />
<br />
Title: Fluctuations for products of random matrices<br />
<br />
Abstract: Products of large random matrices appear in many modern applications such as high dimensional statistics (MANOVA estimators), machine learning (Jacobians of neural networks), and population ecology (transition matrices of dynamical systems). Inspired by these situations, this talk concerns global limits and fluctuations of singular values of products of independent random matrices as both the size N and number M of matrices grow. As N grows, I will show for a variety of ensembles that fluctuations of the Lyapunov exponents converge to explicit Gaussian fields which transition from log-correlated for fixed M to having a white noise component for M growing with N. I will sketch our method, which uses multivariate generalizations of the Laplace transform based on the multivariate Bessel function from representation theory.<br />
<br />
=== Zhenfu Wang (University of Pennsylvania) ===<br />
<br />
Title: Quantitative Methods for the Mean Field Limit Problem<br />
<br />
Abstract: We study the mean field limit of large systems of interacting particles. Classical mean field limit results require that the interaction kernels be essentially Lipschitz. To handle more singular interaction kernels is a longstanding and challenging question but which now has some successes. Joint with P.-E. Jabin, we use the relative entropy between the joint law of all particles and the tensorized law at the limit to quantify the convergence from the particle systems towards the macroscopic PDEs. This method requires to prove large deviations estimates for non-continuous potentials modified by the limiting law. But it leads to explicit convergence rates for all marginals. This in particular can be applied to the Biot-Savart law for 2D Navier-Stokes. To treat more general and singular kernels, joint with D. Bresch and P.-E. Jabin, we introduce the modulated free energy, combination of the relative entropy that we had previously developed and of the modulated energy introduced by S. Serfaty. This modulated free energy may be understood as introducing appropriate weights in the relative entropy to cancel the most singular terms involving the divergence of the kernels. Our modulated free energy allows to treat gradient flows with singular potentials which combine large smooth part, small attractive singular part and large repulsive singular part. As an example, a full rigorous derivation (with quantitative estimates) of some chemotaxis models, such as the Patlak-Keller-Segel system in the subcritical regimes, is obtained.<br />
<br />
== Future Colloquia ==<br />
[[Colloquia/Fall 2020| Fall 2020]]<br />
<br />
== Past Colloquia ==<br />
<br />
[[Colloquia/Fall2019|Fall 2019]]<br />
<br />
[[Colloquia/Spring2019|Spring 2019]]<br />
<br />
[[Colloquia/Fall2018|Fall 2018]]<br />
<br />
[[Colloquia/Spring2018|Spring 2018]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Colloquia/Fall2019&diff=18996Colloquia/Fall20192020-02-11T16:02:05Z<p>Jeanluc: /* Fall 2019 */</p>
<hr />
<div>==Fall 2019==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|Sept 6 '''Room 911'''<br />
| Will Sawin (Columbia)<br />
| [[#Will Sawin (Columbia) | On Chowla's Conjecture over F_q[T] ]]<br />
| Marshall<br />
|-<br />
|Sept 13<br />
| [https://www.math.ksu.edu/~soibel/ Yan Soibelman] (Kansas State)<br />
|[[#Yan Soibelman (Kansas State)| Riemann-Hilbert correspondence and Fukaya categories ]]<br />
| Caldararu<br />
|<br />
|-<br />
|Sept 16 '''Monday Room 911'''<br />
| [http://mate.dm.uba.ar/~alidick/ Alicia Dickenstein] (Buenos Aires)<br />
|[[#Alicia Dickenstein (Buenos Aires)| Algebra and geometry in the study of enzymatic cascades ]]<br />
| Craciun<br />
|<br />
|-<br />
|Sept 20<br />
| [https://math.duke.edu/~jianfeng/ Jianfeng Lu] (Duke)<br />
|[[#Jianfeng Lu (Duke) | How to "localize" the computation?]]<br />
| Qin<br />
|<br />
|-<br />
|Sept 26 '''Thursday 3-4 pm Room 911'''<br />
| [http://eugeniacheng.com/ Eugenia Cheng] (School of the Art Institute of Chicago)<br />
| [[#Eugenia Cheng (School of the Art Institute of Chicago)| Character vs gender in mathematics and beyond ]]<br />
| Marshall / Friends of UW Madison Libraries<br />
|<br />
|-<br />
|Sept 27<br />
|<br />
|<br />
|-<br />
|Oct 4<br />
|<br />
|<br />
|-<br />
|Oct 11<br />
| Omer Mermelstein (Madison)<br />
| [[#Omer Mermelstein (Madison)| Generic flat pregeometries ]]<br />
|Andrews<br />
|<br />
|-<br />
|Oct 18<br />
| Shamgar Gurevich (Madison)<br />
| [[#Shamgar Gurevich (Madison) | Harmonic Analysis on GL(n) over Finite Fields ]]<br />
| Marshall<br />
|-<br />
|Oct 25<br />
|<br />
|-<br />
|Nov 1<br />
|Elchanan Mossel (MIT)<br />
|Distinguished Lecture<br />
|Roch<br />
|-<br />
|Nov 8<br />
|Jose Rodriguez (UW-Madison)<br />
|[[#Jose Rodriguez (UW-Madison) | Nearest Point Problems and Euclidean Distance Degrees]]<br />
|Erman<br />
|-<br />
|Nov 13 '''Wednesday 4-5pm'''<br />
|Ananth Shankar (MIT)<br />
|Exceptional splitting of abelian surfaces<br />
|-<br />
|Nov 20 '''Wednesday 4-5pm'''<br />
|Franca Hoffman (Caltech)<br />
|[[#Franca Hoffman (Caltech) | Gradient Flows: From PDE to Data Analysis]]<br />
|Smith<br />
|-<br />
|Nov 22<br />
| Jeffrey Danciger (UT Austin)<br />
| [[#Jeffrey Danciger (UT Austin) | "Affine geometry and the Auslander Conjecture"]]<br />
| Kent<br />
|-<br />
|Nov 25 '''Monday 4-5 pm Room 911'''<br />
|Tatyana Shcherbina (Princeton)<br />
| [[# Tatyana Shcherbina (Princeton)| "Random matrix theory and supersymmetry techniques"]]<br />
|Roch<br />
|-<br />
|Nov 29<br />
|Thanksgiving<br />
|<br />
|-<br />
|Dec 2 '''Monday 4-5pm'''<br />
|Tingran Gao (University of Chicago)<br />
| [[#Tingran Gao (University of Chicago)| "Manifold Learning on Fibre Bundles"]]<br />
|Smith<br />
|-<br />
|Dec 4 '''Wednesday 4-5 pm Room 911'''<br />
|Andrew Zimmer (LSU)<br />
|[[#Andrew Zimmer (LSU)| "Intrinsic and extrinsic geometries in several complex variables"]]<br />
|Gong<br />
|-<br />
|Dec 6<br />
|Charlotte Chan (MIT)<br />
|[[#Charlotte Chan (MIT)|"Flag varieties and representations of p-adic groups"]]<br />
|Erman<br />
|-<br />
|Dec 9 '''Monday 4-5 pm'''<br />
|Hui Yu (Columbia)<br />
|[[#Hui Yu (Columbia)|Singular sets in obstacle problems]]<br />
|Tran<br />
|-<br />
|Dec 11 '''Wednesday 2:30-3:30pm Room 911'''<br />
|Alex Waldron (Michigan)<br />
|[[#Alex Waldron (Michigan)|Gauge theory and geometric flows]]<br />
|Paul<br />
|-<br />
|Dec 11 '''Wednesday 4-5pm'''<br />
|Nick Higham (Manchester)<br />
|[[#Nick Higham (Manchester)|LAA lecture: Challenges in Multivalued Matrix Functions]]<br />
|Brualdi<br />
|-<br />
|Dec 13 <br />
|Chenxi Wu (Rutgers)<br />
|[[#Chenxi Wu (Rutgers)|Kazhdan's theorem on metric graphs]]<br />
|Ellenberg<br />
|-<br />
|Dec 18 '''Wednesday 4-5pm'''<br />
|Ruobing Zhang (Stony Brook)<br />
|[[#Ruobing Zhang (Stony Brook)|Geometry and analysis of degenerating Calabi-Yau manifolds]]<br />
|Paul<br />
|-<br />
|}<br />
<br />
<br />
== Abstracts ==<br />
<br />
<br />
===Will Sawin (Columbia)===<br />
<br />
Title: On Chowla's Conjecture over F_q[T]<br />
<br />
Abstract: The Mobius function in number theory is a sequences of 1s, <br />
-1s, and 0s, which is simple to define and closely related to the <br />
prime numbers. Its behavior seems highly random. Chowla's conjecture <br />
is one precise formalization of this randomness, and has seen recent <br />
work by Matomaki, Radziwill, Tao, and Teravainen making progress on <br />
it. In joint work with Mark Shusterman, we modify this conjecture by <br />
replacing the natural numbers parameterizing this sequence with <br />
polynomials over a finite field. Under mild conditions on the finite <br />
field, we are able to prove a strong form of this conjecture. The <br />
proof is based on taking a geometric perspective on the problem, and <br />
succeeds because we are able to simplify the geometry using a trick <br />
based on the strange properties of polynomial derivatives over finite <br />
fields.<br />
<br />
<br />
===Yan Soibelman (Kansas State)===<br />
<br />
Title: Riemann-Hilbert correspondence and Fukaya categories<br />
<br />
Abstract: In this talk I am going to discuss the role of Fukaya categories in the Riemann-Hilbert correspondence<br />
for differential, q-difference and elliptic difference equations in dimension one.<br />
This approach not only gives a unified answer for several versions of the Riemann-Hilbert correspondence but also leads to a natural formulation<br />
of the non-abelian Hodge theory in dimension one. It also explains why periodic monopoles<br />
should appear as harmonic objects in this generalized non-abelian Hodge theory.<br />
All that is a part of the bigger project ``Holomorphic Floer theory",<br />
joint with Maxim Kontsevich.<br />
<br />
<br />
===Alicia Dickenstein (Buenos Aires)===<br />
<br />
Title: Algebra and geometry in the study of enzymatic cascades<br />
<br />
Abstract: In recent years, techniques from computational and real algebraic geometry have been successfully used to address mathematical challenges in systems biology. The algebraic theory of chemical reaction systems aims to understand their dynamic behavior by taking advantage of the inherent algebraic structure in the kinetic equations, and does not need the determination of the parameters a priori, which can be theoretically or practically impossible.<br />
I will give a gentle introduction to general results based on the network structure. In particular, I will describe a general framework for biological systems, called MESSI systems, that describe Modifications of type Enzyme-Substrate or Swap with Intermediates, and include many networks that model post-translational modifications of proteins inside the cell. I will also outline recent methods to address the important question of multistationarity, in particular in the study of enzymatic cascades, and will point out some of the mathematical challenges that arise from this application.<br />
<br />
<br />
=== Jianfeng Lu (Duke) ===<br />
Title: How to ``localize" the computation?<br />
<br />
It is often desirable to restrict the numerical computation to a local region to achieve best balance between accuracy and affordability in scientific computing. It is important to avoid artifacts and guarantee predictable modelling while artificial boundary conditions have to be introduced to restrict the computation. In this talk, we will discuss some recent understanding on how to achieve such local computation in the context of topological edge states and elliptic random media.<br />
<br />
<br />
===Eugenia Cheng (School of the Art Institute of Chicago)===<br />
<br />
Title: Character vs gender in mathematics and beyond<br />
<br />
Abstract: This presentation will be based on my experience of being a female mathematician, and teaching mathematics at all levels from elementary school to grad school. The question of why women are under-represented in mathematics is complex and there are no simple answers, only many many contributing factors. I will focus on character traits, and argue that if we focus on this rather than gender we can have a more productive and less divisive conversation. To try and focus on characters rather than genders I will introduce gender-neutral character adjectives "ingressive" and "congressive" to replace masculine and feminine. I will share my experience of teaching congressive abstract mathematics to art students, in a congressive way, and the possible effects this could have for everyone in mathematics, not just women.<br />
<br />
<br />
===Omer Mermelstein (Madison)===<br />
<br />
Title: Generic flat pregeometries<br />
<br />
Abstract: In model theory, the tamest of structures are the strongly minimal ones -- those in which every equation in a single variable has either finitely many or cofinitely many solution. Algebraically closed fields and vector spaces are the canonical examples. Zilber’s conjecture, later refuted by Hrushovski, states that the source of geometric complexity in a strongly minimal structure must be algebraic. The property of "flatness" (strict gammoid) of a geometry (matroid) is that which guarantees Hrushovski's construction is devoid of any associative structure.<br />
The majority of the talk will explain what flatness is, how it should be thought of, and how closely it relates to hypergraphs and Hrushovski's construction method. Model theory makes an appearance only in the second part, where I will share results pertaining to the specific family of geometries arising from Hrushovski's methods.<br />
<br />
<br />
===Shamgar Gurevich (Madison)===<br />
<br />
Title: Harmonic Analysis on GL(n) over Finite Fields.<br />
<br />
Abstract: There are many formulas that express interesting properties of a finite group G in terms of sums over its characters. For evaluating or estimating these sums, one of the most salient quantities to understand is the character ratio:<br />
<br />
trace(ρ(g)) / dim(ρ),<br />
<br />
for an irreducible representation ρ of G and an element g of G. For example, Diaconis and Shahshahani stated a formula of the mentioned type for analyzing certain random walks on G.<br />
<br />
Recently, we discovered that for classical groups G over finite fields there is a natural invariant of representations that provides strong information on the character ratio. We call this invariant rank. <br />
<br />
This talk will discuss the notion of rank for the group GLn over finite fields, demonstrate how it controls the character ratio, and explain how one can apply the results to verify mixing time and rate for certain random walks.<br />
<br />
This is joint work with Roger Howe (Yale and Texas AM). The numerics for this work was carried by Steve Goldstein (Madison)<br />
<br />
<br />
===Jose Rodriguez (UW-Madison)===<br />
<br />
Abstract: Determining the closest point to a model (subset of Euclidean space) is an important problem in many applications in science,<br />
engineering, and statistics. One way to solve this problem is by minimizing the squared Euclidean distance function using a gradient<br />
descent approach. However, when there are multiple local minima, there is no guarantee of convergence to the true global minimizer.<br />
An alternative method is to determine the critical points of an objective function on the model.<br />
In algebraic statistics, the models of interest are algebraic sets, i.e., solution sets to a system of multivariate polynomial equations. In this situation, the number of critical points of the squared Euclidean distance function on the model’s Zariski closure is a topological invariant called the Euclidean distance degree (ED degree).<br />
In this talk, I will present some models from computer vision and statistics that may be described as algebraic sets. Moreover,<br />
I will describe a topological method for determining a Euclidean distance degree and a numerical algebraic geometry approach for<br />
determining critical points of the squared Euclidean distance function.<br />
<br />
<br />
===Ananth Shankar (MIT)===<br />
<br />
Abstract: An abelian surface 'splits' if it admits a non-trivial map to some elliptic curve. It is well known that the set of abelian surfaces that split are sparse in the set of all abelian surfaces. Nevertheless, we prove that there are infinitely many split abelian surfaces in arithmetic one-parameter families of generically non-split abelian surfaces. I will describe this work, and if time permits, mention generalizations of this result to the setting of K3 surfaces, as well as applications to the dynamics of hecke orbits. This is joint work with Tang, Maulik-Tang, and Shankar-Tang-Tayou.<br />
<br />
<br />
===Franca Hoffman (Caltech)===<br />
<br />
Title: Gradient Flows: From PDE to Data Analysis.<br />
<br />
Abstract: Certain diffusive PDEs can be viewed as infinite-dimensional gradient flows. This fact has led to the development of new tools in various areas of mathematics ranging from PDE theory to data science. In this talk, we focus on two different directions: model-driven approaches and data-driven approaches.<br />
In the first part of the talk we use gradient flows for analyzing non-linear and non-local aggregation-diffusion equations when the corresponding energy functionals are not necessarily convex. Moreover, the gradient flow structure enables us to make connections to well-known functional inequalities, revealing possible links between the optimizers of these inequalities and the equilibria of certain aggregation-diffusion PDEs.<br />
In the second part, we use and develop gradient flow theory to design novel tools for data analysis. We draw a connection between gradient flows and Ensemble Kalman methods for parameter estimation. We introduce the Ensemble Kalman Sampler - a derivative-free methodology for model calibration and uncertainty quantification in expensive black-box models. The interacting particle dynamics underlying our algorithm can be approximated by a novel gradient flow structure in a modified Wasserstein metric which reflects particle correlations. The geometry of this modified Wasserstein metric is of independent theoretical interest.<br />
<br />
<br />
=== Jeffrey Danciger (UT Austin) ===<br />
<br />
Title: Affine geometry and the Auslander Conjecture<br />
<br />
Abstract: The Auslander Conjecture is an analogue of Bieberbach’s theory of Euclidean crystallographic groups in the setting of affine geometry. It predicts that a complete affine manifold (a manifold equipped with a complete torsion-free flat affine connection) which is compact must have virtually solvable fundamental group. The conjecture is known up to dimension six, but is known to fail if the compactness assumption is removed, even in low dimensions. We discuss some history of this conjecture, give some basic examples, and then survey some recent advances in the study of non-compact complete affine manifolds with non-solvable fundamental group. <br />
Tools from the deformation theory of pseudo-Riemannian hyperbolic manifolds and also from higher Teichm&uuml;ller theory will enter the picture.<br />
<br />
<br />
=== Tatyana Shcherbina (Princeton) ===<br />
<br />
Title: Random matrix theory and supersymmetry techniques<br />
<br />
Abstract: Starting from the works of Erdos, Yau, Schlein with coauthors, the significant progress in understanding the universal behavior of many random graph and random matrix models were achieved. However for the random matrices with a special structure our understanding is still very limited. In this talk I am going to overview applications of another approach to the study of the local eigenvalues statistics in random matrix theory based on so-called supersymmetry techniques (SUSY). SUSY approach is based on the representation of the determinant as an integral over the Grassmann (anticommuting) variables. Combining this representation with the representation of an inverse determinant as an integral over the Gaussian complex field, SUSY allows to obtain an integral representation for the main spectral characteristics of random matrices such as limiting density, correlation functions, the resolvent's elements, etc. This method is widely (and successfully) used in the physics literature and is potentially very powerful but the rigorous control of the integral representations, which can be obtained by this method, is quite difficult, and it requires powerful analytic and statistical mechanics tools. In this talk we will discuss some recent progress in application of SUSY to the analysis of local spectral characteristics of the prominent ensemble of random band matrices, i.e. random matrices<br />
whose entries become negligible if their distance from the main diagonal exceeds a certain parameter called the band width. <br />
<br />
<br />
=== Tingran Gao (University of Chicago) ===<br />
<br />
Title: Manifold Learning on Fibre Bundles<br />
<br />
Abstract: Spectral geometry has played an important role in modern geometric data analysis, where the technique is widely known as Laplacian eigenmaps or diffusion maps. In this talk, we present a geometric framework that studies graph representations of complex datasets, where each edge of the graph is equipped with a non-scalar transformation or correspondence. This new framework models such a dataset as a fibre bundle with a connection, and interprets the collection of pairwise functional relations as defining a horizontal diffusion process on the bundle driven by its projection on the base. The eigenstates of this horizontal diffusion process encode the “consistency” among objects in the dataset, and provide a lens through which the geometry of the dataset can be revealed. We demonstrate an application of this geometric framework on evolutionary anthropology.<br />
<br />
<br />
=== Andrew Zimmer (LSU) ===<br />
<br />
Title: Intrinsic and extrinsic geometries in several complex variables<br />
<br />
Abstract: A bounded domain in complex Euclidean space, despite being one of the simplest types of manifolds, has a number of interesting geometric structures. When the domain is pseudoconvex, it has a natural intrinsic geometry: the complete Kaehler-Einstein metric constructed by Cheng-Yau and Mok-Yau. When the domain is smoothly bounded, there is also a natural extrinsic structure: the CR-geometry of the boundary. In this talk, I will describe connections between these intrinsic and extrinsic geometries. Then, I will discuss how these connections can lead to new analytic results.<br />
<br />
=== Charlotte Chan (MIT) ===<br />
<br />
Title: Flag varieties and representations of p-adic groups<br />
<br />
Abstract: In the 1950s, Borel, Weil, and Bott showed that the<br />
irreducible representations of a complex reductive group can be<br />
realized in the cohomology of line bundles on flag varieties. In the<br />
1970s, Deligne and Lusztig constructed a family of subvarieties of<br />
flag varieties whose cohomology realizes the irreducible<br />
representations of reductive groups over finite fields. I will survey<br />
these stories, explain recent progress towards finding geometric<br />
constructions of representations of p-adic groups, and discuss<br />
interactions with the Langlands program.<br />
<br />
=== Hui Yu (Columbia) ===<br />
<br />
Title: Singular sets in obstacle problems<br />
<br />
Abstract: One of the most important free boundary problems is the obstacle problem. The regularity of its free boundary has been studied for over half a century. In this talk, we review some classical results as well as exciting new developments. In particular, we discuss the recent resolution of the regularity of the singular set for the fully nonlinear obstacle problem. This talk is based on a joint work with Ovidiu Savin at Columbia University.<br />
<br />
=== Alex Waldron (Michigan) ===<br />
<br />
Title: Gauge theory and geometric flows<br />
<br />
Abstract: I will give a brief introduction to two major areas of research in differential geometry: gauge theory and geometric flows. I'll then introduce a geometric flow (Yang-Mills flow) arising from a variational problem with origins in physics, which has been studied by geometric analysts since the early 1980s. I'll conclude by discussing my own work on the behavior of Yang-Mills flow in the critical dimension (n = 4).<br />
<br />
=== Nick Higham (Manchester) ===<br />
<br />
Title: Challenges in Multivalued Matrix Functions<br />
<br />
Abstract: In this lecture I will discuss multivalued matrix functions that arise in solving various kinds of matrix equations. The matrix logarithm is the prototypical example, and my first interaction with Hans Schneider was about this function. Another example is the Lambert W function of a matrix, which is much less well known but has been attracting recent interest. A theme of the talk is the importance of choosing appropriate principal values and making sure that the correct choices of signs and branches are used,<br />
both in theory and in computation. I will give examples where incorrect results have previously been obtained.<br />
<br />
I focus on matrix inverse trigonometric and inverse hyperbolic functions, beginning by investigating existence and characterization. Turning to the principal values, various functional identities are derived, some of which are new even in the scalar case, including a “round trip” formula that relates acos(cos A) to A and similar formulas for the other inverse functions. Key tools used in the derivations are the matrix unwinding function and the matrix sign function.<br />
<br />
A new inverse scaling and squaring type algorithm employing a Schur decomposition and variable-degree Pade approximation is derived for computing acos, and it is shown how it can also be used to compute asin, acosh, and asinh.<br />
<br />
=== Chenxi Wu (Rutgers) ===<br />
<br />
Title: Kazhdan's theorem on metric graphs<br />
<br />
Abstract: I will give an introduction to the concept of canonical (arakelov) metric on a metric graph, which is related to combinatorial questions like the counting of spanning trees, and generalizes the corresponding concept on Riemann surfaces. I will also present a recent result in collaboration with Farbod Shokrieh on the convergence of canonical metric under normal covers.<br />
<br />
=== Ruobing Zhang (Stony Brook) ===<br />
<br />
Title: Geometry and analysis of degenerating Calabi-Yau manifolds<br />
<br />
Abstract: This talk concerns a naturally occurring family of degenerating Calabi-Yau manifolds. A primary tool in analyzing their behavior is to combine the recently developed structure theory for Einstein manifolds and multi-scale singularity analysis for degenerating nonlinear PDEs in the collapsed setting. Based on the algebraic degeneration, we will give precise and more quantitative descriptions of singularity formation from both metric and analytic points of view.</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Colloquia/Fall2019&diff=18995Colloquia/Fall20192020-02-11T15:59:36Z<p>Jeanluc: Created page with "==Fall 2019== {| cellpadding="8" !align="left" | date !align="left" | speaker !align="left" | title !align="left" | host(s) |- |Sept 6 '''Room 911''' | Will Sawin (Columbi..."</p>
<hr />
<div>==Fall 2019==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|Sept 6 '''Room 911'''<br />
| Will Sawin (Columbia)<br />
| [[#Will Sawin (Columbia) | On Chowla's Conjecture over F_q[T] ]]<br />
| Marshall<br />
|-<br />
|Sept 13<br />
| [https://www.math.ksu.edu/~soibel/ Yan Soibelman] (Kansas State)<br />
|[[#Yan Soibelman (Kansas State)| Riemann-Hilbert correspondence and Fukaya categories ]]<br />
| Caldararu<br />
|<br />
|-<br />
|Sept 16 '''Monday Room 911'''<br />
| [http://mate.dm.uba.ar/~alidick/ Alicia Dickenstein] (Buenos Aires)<br />
|[[#Alicia Dickenstein (Buenos Aires)| Algebra and geometry in the study of enzymatic cascades ]]<br />
| Craciun<br />
|<br />
|-<br />
|Sept 20<br />
| [https://math.duke.edu/~jianfeng/ Jianfeng Lu] (Duke)<br />
|[[#Jianfeng Lu (Duke) | How to "localize" the computation?]]<br />
| Qin<br />
|<br />
|-<br />
|Sept 26 '''Thursday 3-4 pm Room 911'''<br />
| [http://eugeniacheng.com/ Eugenia Cheng] (School of the Art Institute of Chicago)<br />
| [[#Eugenia Cheng (School of the Art Institute of Chicago)| Character vs gender in mathematics and beyond ]]<br />
| Marshall / Friends of UW Madison Libraries<br />
|<br />
|-<br />
|Sept 27<br />
|<br />
|<br />
|-<br />
|Oct 4<br />
|<br />
|<br />
|-<br />
|Oct 11<br />
| Omer Mermelstein (Madison)<br />
| [[#Omer Mermelstein (Madison)| Generic flat pregeometries ]]<br />
|Andrews<br />
|<br />
|-<br />
|Oct 18<br />
| Shamgar Gurevich (Madison)<br />
| [[#Shamgar Gurevich (Madison) | Harmonic Analysis on GL(n) over Finite Fields ]]<br />
| Marshall<br />
|-<br />
|Oct 25<br />
|<br />
|-<br />
|Nov 1<br />
|Elchanan Mossel (MIT)<br />
|Distinguished Lecture<br />
|Roch<br />
|-<br />
|Nov 8<br />
|Jose Rodriguez (UW-Madison)<br />
|[[#Jose Rodriguez (UW-Madison) | Nearest Point Problems and Euclidean Distance Degrees]]<br />
|Erman<br />
|-<br />
|Nov 13 '''Wednesday 4-5pm'''<br />
|Ananth Shankar (MIT)<br />
|Exceptional splitting of abelian surfaces<br />
|-<br />
|Nov 20 '''Wednesday 4-5pm'''<br />
|Franca Hoffman (Caltech)<br />
|[[#Franca Hoffman (Caltech) | Gradient Flows: From PDE to Data Analysis]]<br />
|Smith<br />
|-<br />
|Nov 22<br />
| Jeffrey Danciger (UT Austin)<br />
| [[#Jeffrey Danciger (UT Austin) | "Affine geometry and the Auslander Conjecture"]]<br />
| Kent<br />
|-<br />
|Nov 25 '''Monday 4-5 pm Room 911'''<br />
|Tatyana Shcherbina (Princeton)<br />
| [[# Tatyana Shcherbina (Princeton)| "Random matrix theory and supersymmetry techniques"]]<br />
|Roch<br />
|-<br />
|Nov 29<br />
|Thanksgiving<br />
|<br />
|-<br />
|Dec 2 '''Monday 4-5pm'''<br />
|Tingran Gao (University of Chicago)<br />
| [[#Tingran Gao (University of Chicago)| "Manifold Learning on Fibre Bundles"]]<br />
|Smith<br />
|-<br />
|Dec 4 '''Wednesday 4-5 pm Room 911'''<br />
|Andrew Zimmer (LSU)<br />
|[[#Andrew Zimmer (LSU)| "Intrinsic and extrinsic geometries in several complex variables"]]<br />
|Gong<br />
|-<br />
|Dec 6<br />
|Charlotte Chan (MIT)<br />
|[[#Charlotte Chan (MIT)|"Flag varieties and representations of p-adic groups"]]<br />
|Erman<br />
|-<br />
|Dec 9 '''Monday 4-5 pm'''<br />
|Hui Yu (Columbia)<br />
|[[#Hui Yu (Columbia)|Singular sets in obstacle problems]]<br />
|Tran<br />
|-<br />
|Dec 11 '''Wednesday 2:30-3:30pm Room 911'''<br />
|Alex Waldron (Michigan)<br />
|[[#Alex Waldron (Michigan)|Gauge theory and geometric flows]]<br />
|Paul<br />
|-<br />
|Dec 11 '''Wednesday 4-5pm'''<br />
|Nick Higham (Manchester)<br />
|[[#Nick Higham (Manchester)|LAA lecture: Challenges in Multivalued Matrix Functions]]<br />
|Brualdi<br />
|-<br />
|Dec 13 <br />
|Chenxi Wu (Rutgers)<br />
|[[#Chenxi Wu (Rutgers)|Kazhdan's theorem on metric graphs]]<br />
|Ellenberg<br />
|-<br />
|Dec 18 '''Wednesday 4-5pm'''<br />
|Ruobing Zhang (Stony Brook)<br />
|[[#Ruobing Zhang (Stony Brook)|Geometry and analysis of degenerating Calabi-Yau manifolds]]<br />
|Paul<br />
|-<br />
|}</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=18863Applied/Physical Applied Math2020-02-01T20:44:35Z<p>Jeanluc: /* Spring 2020 */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a [https://www.math.wisc.edu/deptmeetings Department Meeting])<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 30<br />
|Jean-Luc<br />
|Organizational meeting; [https://www.dropbox.com/s/bnjpyud6h8u3lav/homog_periodic_lattice_group_meeting.pdf?dl=0 Homogenization of a periodic lattice]<br />
|-<br />
|Feb. 6<br />
|Gage<br />
|Krasilov et al., [https://bura.brunel.ac.uk/bitstream/2438/419/1/Growing%20Random%20Sequences.pdf Growing random sequences]<br> Makover and McGowan, [https://arxiv.org/abs/math/0510159 An elementary proof that random Fibonacci sequences grow exponentially]<br />
|-<br />
|Feb. 13<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 20<br />
|Saverio<br />
|<br />
|-<br />
|Feb. 27<br />
|Wil<br />
|''EC?''<br />
|-<br />
|Mar. 5<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Mar. 12<br />
|Ruifu<br />
|''EC?''<br />
|-<br />
|Mar. 19<br />
|<br />
|''Spring Break''<br />
|-<br />
|Mar. 26<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 2<br />
|Keaton Burns?<br />
|<br />
|-<br />
|Apr. 9<br />
|<br />
|<br />
|-<br />
|Apr. 16<br />
|<br />
|<br />
|-<br />
|Apr. 23<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 30<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Fall2019|Fall 2019]]<br />
*[[Applied/Physical_Applied_Math/Spring2019|Spring 2019]]<br />
*[[Applied/Physical_Applied_Math/Fall2018|Fall 2018]]<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=18862Applied/Physical Applied Math2020-02-01T20:39:33Z<p>Jeanluc: /* Spring 2020 */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a [https://www.math.wisc.edu/deptmeetings Department Meeting])<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 30<br />
|Jean-Luc<br />
|Organizational meeting; [https://www.dropbox.com/s/bnjpyud6h8u3lav/homog_periodic_lattice_group_meeting.pdf?dl=0 Homogenization of a periodic lattice]<br />
|-<br />
|Feb. 6<br />
|Gage<br />
|<br />
|-<br />
|Feb. 13<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 20<br />
|Saverio<br />
|<br />
|-<br />
|Feb. 27<br />
|Wil<br />
|''EC?''<br />
|-<br />
|Mar. 5<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Mar. 12<br />
|Ruifu<br />
|''EC?''<br />
|-<br />
|Mar. 19<br />
|<br />
|''Spring Break''<br />
|-<br />
|Mar. 26<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 2<br />
|Keaton Burns?<br />
|<br />
|-<br />
|Apr. 9<br />
|<br />
|<br />
|-<br />
|Apr. 16<br />
|<br />
|<br />
|-<br />
|Apr. 23<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 30<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Fall2019|Fall 2019]]<br />
*[[Applied/Physical_Applied_Math/Spring2019|Spring 2019]]<br />
*[[Applied/Physical_Applied_Math/Fall2018|Fall 2018]]<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=18848Applied/Physical Applied Math2020-01-31T15:11:43Z<p>Jeanluc: /* Spring 2020 */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a [https://www.math.wisc.edu/deptmeetings Department Meeting])<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 30<br />
|Jean-Luc<br />
|Organizational meeting; [https://www.dropbox.com/s/bnjpyud6h8u3lav/homog_periodic_lattice_group_meeting.pdf?dl=0 Homogenization of a periodic lattice]<br />
|-<br />
|Feb. 6<br />
|Gage<br />
|<br />
|-<br />
|Feb. 13<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 20<br />
|Saverio<br />
|<br />
|-<br />
|Feb. 27<br />
|Wil<br />
|''EC?''<br />
|-<br />
|Mar. 5<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Mar. 12<br />
|<br />
|''EC?''<br />
|-<br />
|Mar. 19<br />
|<br />
|''Spring Break''<br />
|-<br />
|Mar. 26<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 2<br />
|Keaton Burns?<br />
|<br />
|-<br />
|Apr. 9<br />
|<br />
|<br />
|-<br />
|Apr. 16<br />
|<br />
|<br />
|-<br />
|Apr. 23<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 30<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Fall2019|Fall 2019]]<br />
*[[Applied/Physical_Applied_Math/Spring2019|Spring 2019]]<br />
*[[Applied/Physical_Applied_Math/Fall2018|Fall 2018]]<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=18847Applied/Physical Applied Math2020-01-31T15:08:40Z<p>Jeanluc: /* Spring 2020 */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a [https://www.math.wisc.edu/deptmeetings Department Meeting])<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 30<br />
|Jean-Luc<br />
|Organizational meeting; [https://www.dropbox.com/s/bnjpyud6h8u3lav/homog_periodic_lattice_group_meeting.pdf?dl=0 Homogenization of a periodic lattice]<br />
|-<br />
|Feb. 6<br />
|Gage<br />
|<br />
|-<br />
|Feb. 13<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 20<br />
|Saverio<br />
|<br />
|-<br />
|Feb. 27<br />
|Wil<br />
|''EC?''<br />
|-<br />
|Mar. 5<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Mar. 12<br />
|<br />
|''EC?''<br />
|-<br />
|Mar. 19<br />
|<br />
|''Spring Break''<br />
|-<br />
|Mar. 26<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 2<br />
|<br />
|<br />
|-<br />
|Apr. 9<br />
|<br />
|<br />
|-<br />
|Apr. 16<br />
|<br />
|<br />
|-<br />
|Apr. 23<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 30<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Fall2019|Fall 2019]]<br />
*[[Applied/Physical_Applied_Math/Spring2019|Spring 2019]]<br />
*[[Applied/Physical_Applied_Math/Fall2018|Fall 2018]]<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=18836Applied/Physical Applied Math2020-01-30T21:36:25Z<p>Jeanluc: /* Spring 2020 */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a [https://www.math.wisc.edu/deptmeetings Department Meeting])<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 30<br />
|Jean-Luc<br />
|Organizational meeting; [https://www.dropbox.com/s/bnjpyud6h8u3lav/homog_periodic_lattice_group_meeting.pdf?dl=0 Homogenization of a periodic lattice]<br />
|-<br />
|Feb. 6<br />
|<br />
|<br />
|-<br />
|Feb. 13<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 20<br />
|<br />
|<br />
|-<br />
|Feb. 27<br />
|<br />
|''EC?''<br />
|-<br />
|Mar. 5<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Mar. 12<br />
|<br />
|''EC?''<br />
|-<br />
|Mar. 19<br />
|<br />
|''Spring Break''<br />
|-<br />
|Mar. 26<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 2<br />
|<br />
|<br />
|-<br />
|Apr. 9<br />
|<br />
|<br />
|-<br />
|Apr. 16<br />
|<br />
|<br />
|-<br />
|Apr. 23<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 30<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Fall2019|Fall 2019]]<br />
*[[Applied/Physical_Applied_Math/Spring2019|Spring 2019]]<br />
*[[Applied/Physical_Applied_Math/Fall2018|Fall 2018]]<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=18831Applied/Physical Applied Math2020-01-30T18:08:08Z<p>Jeanluc: /* Physical Applied Math Group Meeting */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a [https://www.math.wisc.edu/deptmeetings Department Meeting])<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 30<br />
|<br />
|Organizational meeting<br />
|-<br />
|Feb. 6<br />
|<br />
|<br />
|-<br />
|Feb. 13<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 20<br />
|<br />
|<br />
|-<br />
|Feb. 27<br />
|<br />
|''EC?''<br />
|-<br />
|Mar. 5<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Mar. 12<br />
|<br />
|''EC?''<br />
|-<br />
|Mar. 19<br />
|<br />
|''Spring Break''<br />
|-<br />
|Mar. 26<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 2<br />
|<br />
|<br />
|-<br />
|Apr. 9<br />
|<br />
|<br />
|-<br />
|Apr. 16<br />
|<br />
|<br />
|-<br />
|Apr. 23<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 30<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Fall2019|Fall 2019]]<br />
*[[Applied/Physical_Applied_Math/Spring2019|Spring 2019]]<br />
*[[Applied/Physical_Applied_Math/Fall2018|Fall 2018]]<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=18830Applied/Physical Applied Math2020-01-30T18:07:15Z<p>Jeanluc: /* Archived semesters */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a departmental meeting)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 30<br />
|<br />
|Organizational meeting<br />
|-<br />
|Feb. 6<br />
|<br />
|<br />
|-<br />
|Feb. 13<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 20<br />
|<br />
|<br />
|-<br />
|Feb. 27<br />
|<br />
|''EC?''<br />
|-<br />
|Mar. 5<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Mar. 12<br />
|<br />
|''EC?''<br />
|-<br />
|Mar. 19<br />
|<br />
|''Spring Break''<br />
|-<br />
|Mar. 26<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 2<br />
|<br />
|<br />
|-<br />
|Apr. 9<br />
|<br />
|<br />
|-<br />
|Apr. 16<br />
|<br />
|<br />
|-<br />
|Apr. 23<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 30<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Fall2019|Fall 2019]]<br />
*[[Applied/Physical_Applied_Math/Spring2019|Spring 2019]]<br />
*[[Applied/Physical_Applied_Math/Fall2018|Fall 2018]]<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=18829Applied/Physical Applied Math2020-01-30T18:06:54Z<p>Jeanluc: /* Fall 2019 */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a departmental meeting)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 30<br />
|<br />
|Organizational meeting<br />
|-<br />
|Feb. 6<br />
|<br />
|<br />
|-<br />
|Feb. 13<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 20<br />
|<br />
|<br />
|-<br />
|Feb. 27<br />
|<br />
|''EC?''<br />
|-<br />
|Mar. 5<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Mar. 12<br />
|<br />
|''EC?''<br />
|-<br />
|Mar. 19<br />
|<br />
|''Spring Break''<br />
|-<br />
|Mar. 26<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 2<br />
|<br />
|<br />
|-<br />
|Apr. 9<br />
|<br />
|<br />
|-<br />
|Apr. 16<br />
|<br />
|<br />
|-<br />
|Apr. 23<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 30<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Spring2019|Spring 2019]]<br />
*[[Applied/Physical_Applied_Math/Fall2018|Fall 2018]]<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math/Fall2019&diff=18828Applied/Physical Applied Math/Fall20192020-01-30T17:42:33Z<p>Jeanluc: Created page with "== Fall 2019 == {| cellpadding="8" !align="left" | date !align="left" | speaker !align="left" | title |- |Sept. 5 | |Organizational meeting |- |Sept. 12 | |''Faculty Meetin..."</p>
<hr />
<div>== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Sept. 5<br />
|<br />
|Organizational meeting<br />
|-<br />
|Sept. 12<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Sept. 19<br />
|Yu<br />
|Convection-induced singularity suppression in the Keller-Segel and other nonlinear PDEs<br />
|-<br />
|Sept. 26<br />
|Son<br />
|State-constraint static Hamilton-Jacobi equations in nested domains<br />
|-<br />
|Oct. 3<br />
|Hongfei<br />
|Microswimmers interacting with walls<br />
|-<br />
|Oct. 10<br />
|Alex Townsend<br />
|The ultraspherical spectral method<br />
|-<br />
|Oct. 17<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Oct. 24<br />
|Prerna<br />
||Pak, Feng and Stone, [https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/viscous-marangoni-migration-of-a-drop-in-a-poiseuille-flow-at-low-surface-peclet-numbers/2504CA0D4BC84B06E2E33DA39DE93355 Viscous Marangoni migration of a drop in a Poiseuille flow at low surface Péclet numbers].<br />
|-<br />
|Oct. 31<br />
|''no meeting''<br />
|<br />
|-<br />
|Nov. 7<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Nov. 14<br />
|Bryan<br />
|Vanneste, [https://journals.aps.org/pre/abstract/10.1103/PhysRevE.81.036701 Estimating generalized Lyapunov exponents for products of random matrices]<br />
|-<br />
|Nov. 21<br />
|<br />
|Practice talks for DFD<br />
|-<br />
|Dec. 5<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Dec. 12<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|}</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Colloquia&diff=18502Colloquia2019-11-28T19:01:17Z<p>Jeanluc: /* Abstracts */</p>
<hr />
<div>= Mathematics Colloquium =<br />
<br />
All colloquia are on Fridays at 4:00 pm in Van Vleck B239, '''unless otherwise indicated'''.<br />
<br />
<br />
<br />
==Fall 2019==<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|Sept 6 '''Room 911'''<br />
| Will Sawin (Columbia)<br />
| [[#Will Sawin (Columbia) | On Chowla's Conjecture over F_q[T] ]]<br />
| Marshall<br />
|-<br />
|Sept 13<br />
| [https://www.math.ksu.edu/~soibel/ Yan Soibelman] (Kansas State)<br />
|[[#Yan Soibelman (Kansas State)| Riemann-Hilbert correspondence and Fukaya categories ]]<br />
| Caldararu<br />
|<br />
|-<br />
|Sept 16 '''Monday Room 911'''<br />
| [http://mate.dm.uba.ar/~alidick/ Alicia Dickenstein] (Buenos Aires)<br />
|[[#Alicia Dickenstein (Buenos Aires)| Algebra and geometry in the study of enzymatic cascades ]]<br />
| Craciun<br />
|<br />
|-<br />
|Sept 20<br />
| [https://math.duke.edu/~jianfeng/ Jianfeng Lu] (Duke)<br />
|[[#Jianfeng Lu (Duke) | How to "localize" the computation?]]<br />
| Qin<br />
|<br />
|-<br />
|Sept 26 '''Thursday 3-4 pm Room 911'''<br />
| [http://eugeniacheng.com/ Eugenia Cheng] (School of the Art Institute of Chicago)<br />
| [[#Eugenia Cheng (School of the Art Institute of Chicago)| Character vs gender in mathematics and beyond ]]<br />
| Marshall / Friends of UW Madison Libraries<br />
|<br />
|-<br />
|Sept 27<br />
|<br />
|<br />
|-<br />
|Oct 4<br />
|<br />
|<br />
|-<br />
|Oct 11<br />
| Omer Mermelstein (Madison)<br />
| [[#Omer Mermelstein (Madison)| Generic flat pregeometries ]]<br />
|Andrews<br />
|<br />
|-<br />
|Oct 18<br />
| Shamgar Gurevich (Madison)<br />
| [[#Shamgar Gurevich (Madison) | Harmonic Analysis on GL(n) over Finite Fields ]]<br />
| Marshall<br />
|-<br />
|Oct 25<br />
|<br />
|-<br />
|Nov 1<br />
|Elchanan Mossel (MIT)<br />
|Distinguished Lecture<br />
|Roch<br />
|-<br />
|Nov 8<br />
|Jose Rodriguez (UW-Madison)<br />
|[[#Jose Rodriguez (UW-Madison) | Nearest Point Problems and Euclidean Distance Degrees]]<br />
|Erman<br />
|-<br />
|Nov 13 '''Wednesday 4-5pm'''<br />
|Ananth Shankar (MIT)<br />
|Exceptional splitting of abelian surfaces<br />
|-<br />
|Nov 20 '''Wednesday 4-5pm'''<br />
|Franca Hoffman (Caltech)<br />
|[[#Franca Hoffman (Caltech) | Gradient Flows: From PDE to Data Analysis]]<br />
|Smith<br />
|-<br />
|Nov 22<br />
| Jeffrey Danciger (UT Austin)<br />
| [[#Jeffrey Danciger (UT Austin) | "Affine geometry and the Auslander Conjecture"]]<br />
| Kent<br />
|-<br />
|Nov 25 '''Monday 4-5 pm Room 911'''<br />
|Tatyana Shcherbina (Princeton)<br />
| [[# Tatyana Shcherbina (Princeton)| "Random matrix theory and supersymmetry techniques"]]<br />
|Roch<br />
|-<br />
|Nov 29<br />
|Thanksgiving<br />
|<br />
|-<br />
|Dec 2 '''Monday 4-5pm'''<br />
|Tingran Gao (University of Chicago)<br />
| [[#Tingran Gao (University of Chicago)| "Manifold Learning on Fibre Bundles"]]<br />
|Smith<br />
|-<br />
|Dec 4 '''Wednesday 4-5 pm'''<br />
|Andrew Zimmer<br />
| Intrinsic and extrinsic geometries in several complex variables<br />
|Gong<br />
|-<br />
|Dec 6<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Dec 9 '''Monday 4-5 pm'''<br />
|Hui Yu (Columbia)<br />
|[[#Hui Yu (Columbia)|Singular sets in obstacle problems]]<br />
|Tran<br />
|-<br />
|Dec 11 '''Wednesday'''<br />
|Nick Higham (Manchester)<br />
|[[#Nick Higham (Manchester)|LAA lecture: Challenges in Multivalued Matrix Functions]]<br />
|Brualdi<br />
|<br />
|-<br />
|Dec 13<br />
|Reserved for job talk<br />
|<br />
|}<br />
<br />
==Spring 2020==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|<br />
|-<br />
|Jan 24<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Jan 29 '''Wednesday 4-5 pm'''<br />
|[https://ajzucker.wordpress.com/ Andy Zucker] (Lyon)<br />
|<br />
|Soskova/Lempp<br />
|<br />
|-<br />
|Jan 31<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Feb 7<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Feb 14<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Feb 21<br />
|Shai Evra (IAS)<br />
|<br />
|Gurevich<br />
|<br />
|-<br />
|Feb 28<br />
|Brett Wick (Washington University, St. Louis)<br />
|<br />
|Seeger<br />
|-<br />
|March 6<br />
| Jessica Fintzen (Michigan)<br />
|<br />
|Marshall<br />
|-<br />
|March 13<br />
|<br />
|-<br />
|March 20<br />
|Spring break<br />
|<br />
|-<br />
|March 27<br />
|(Moduli Spaces Conference)<br />
|<br />
|Boggess, Sankar<br />
|-<br />
|April 3<br />
|Caroline Turnage-Butterbaugh (Carleton College)<br />
|<br />
|Marshall<br />
|-<br />
|April 10<br />
| Sarah Koch (Michigan)<br />
|<br />
| Bruce (WIMAW)<br />
|-<br />
|April 17<br />
|Song Sun (Berkeley)<br />
|<br />
|Huang<br />
|-<br />
|April 24<br />
|Natasa Sesum (Rutgers University)<br />
|<br />
|Angenent<br />
|-<br />
|May 1<br />
|Robert Lazarsfeld (Stony Brook)<br />
|Distinguished lecture<br />
|Erman<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
<br />
===Will Sawin (Columbia)===<br />
<br />
Title: On Chowla's Conjecture over F_q[T]<br />
<br />
Abstract: The Mobius function in number theory is a sequences of 1s, <br />
-1s, and 0s, which is simple to define and closely related to the <br />
prime numbers. Its behavior seems highly random. Chowla's conjecture <br />
is one precise formalization of this randomness, and has seen recent <br />
work by Matomaki, Radziwill, Tao, and Teravainen making progress on <br />
it. In joint work with Mark Shusterman, we modify this conjecture by <br />
replacing the natural numbers parameterizing this sequence with <br />
polynomials over a finite field. Under mild conditions on the finite <br />
field, we are able to prove a strong form of this conjecture. The <br />
proof is based on taking a geometric perspective on the problem, and <br />
succeeds because we are able to simplify the geometry using a trick <br />
based on the strange properties of polynomial derivatives over finite <br />
fields.<br />
<br />
<br />
===Yan Soibelman (Kansas State)===<br />
<br />
Title: Riemann-Hilbert correspondence and Fukaya categories<br />
<br />
Abstract: In this talk I am going to discuss the role of Fukaya categories in the Riemann-Hilbert correspondence<br />
for differential, q-difference and elliptic difference equations in dimension one.<br />
This approach not only gives a unified answer for several versions of the Riemann-Hilbert correspondence but also leads to a natural formulation<br />
of the non-abelian Hodge theory in dimension one. It also explains why periodic monopoles<br />
should appear as harmonic objects in this generalized non-abelian Hodge theory.<br />
All that is a part of the bigger project ``Holomorphic Floer theory",<br />
joint with Maxim Kontsevich.<br />
<br />
<br />
===Alicia Dickenstein (Buenos Aires)===<br />
<br />
Title: Algebra and geometry in the study of enzymatic cascades<br />
<br />
Abstract: In recent years, techniques from computational and real algebraic geometry have been successfully used to address mathematical challenges in systems biology. The algebraic theory of chemical reaction systems aims to understand their dynamic behavior by taking advantage of the inherent algebraic structure in the kinetic equations, and does not need the determination of the parameters a priori, which can be theoretically or practically impossible.<br />
I will give a gentle introduction to general results based on the network structure. In particular, I will describe a general framework for biological systems, called MESSI systems, that describe Modifications of type Enzyme-Substrate or Swap with Intermediates, and include many networks that model post-translational modifications of proteins inside the cell. I will also outline recent methods to address the important question of multistationarity, in particular in the study of enzymatic cascades, and will point out some of the mathematical challenges that arise from this application.<br />
<br />
<br />
=== Jianfeng Lu (Duke) ===<br />
Title: How to ``localize" the computation?<br />
<br />
It is often desirable to restrict the numerical computation to a local region to achieve best balance between accuracy and affordability in scientific computing. It is important to avoid artifacts and guarantee predictable modelling while artificial boundary conditions have to be introduced to restrict the computation. In this talk, we will discuss some recent understanding on how to achieve such local computation in the context of topological edge states and elliptic random media.<br />
<br />
<br />
===Eugenia Cheng (School of the Art Institute of Chicago)===<br />
<br />
Title: Character vs gender in mathematics and beyond<br />
<br />
Abstract: This presentation will be based on my experience of being a female mathematician, and teaching mathematics at all levels from elementary school to grad school. The question of why women are under-represented in mathematics is complex and there are no simple answers, only many many contributing factors. I will focus on character traits, and argue that if we focus on this rather than gender we can have a more productive and less divisive conversation. To try and focus on characters rather than genders I will introduce gender-neutral character adjectives "ingressive" and "congressive" to replace masculine and feminine. I will share my experience of teaching congressive abstract mathematics to art students, in a congressive way, and the possible effects this could have for everyone in mathematics, not just women.<br />
<br />
<br />
===Omer Mermelstein (Madison)===<br />
<br />
Title: Generic flat pregeometries<br />
<br />
Abstract: In model theory, the tamest of structures are the strongly minimal ones -- those in which every equation in a single variable has either finitely many or cofinitely many solution. Algebraically closed fields and vector spaces are the canonical examples. Zilber’s conjecture, later refuted by Hrushovski, states that the source of geometric complexity in a strongly minimal structure must be algebraic. The property of "flatness" (strict gammoid) of a geometry (matroid) is that which guarantees Hrushovski's construction is devoid of any associative structure.<br />
The majority of the talk will explain what flatness is, how it should be thought of, and how closely it relates to hypergraphs and Hrushovski's construction method. Model theory makes an appearance only in the second part, where I will share results pertaining to the specific family of geometries arising from Hrushovski's methods.<br />
<br />
<br />
===Shamgar Gurevich (Madison)===<br />
<br />
Title: Harmonic Analysis on GL(n) over Finite Fields.<br />
<br />
Abstract: There are many formulas that express interesting properties of a finite group G in terms of sums over its characters. For evaluating or estimating these sums, one of the most salient quantities to understand is the character ratio:<br />
<br />
trace(ρ(g)) / dim(ρ),<br />
<br />
for an irreducible representation ρ of G and an element g of G. For example, Diaconis and Shahshahani stated a formula of the mentioned type for analyzing certain random walks on G.<br />
<br />
Recently, we discovered that for classical groups G over finite fields there is a natural invariant of representations that provides strong information on the character ratio. We call this invariant rank. <br />
<br />
This talk will discuss the notion of rank for the group GLn over finite fields, demonstrate how it controls the character ratio, and explain how one can apply the results to verify mixing time and rate for certain random walks.<br />
<br />
This is joint work with Roger Howe (Yale and Texas AM). The numerics for this work was carried by Steve Goldstein (Madison)<br />
<br />
<br />
===Jose Rodriguez (UW-Madison)===<br />
<br />
Abstract: Determining the closest point to a model (subset of Euclidean space) is an important problem in many applications in science,<br />
engineering, and statistics. One way to solve this problem is by minimizing the squared Euclidean distance function using a gradient<br />
descent approach. However, when there are multiple local minima, there is no guarantee of convergence to the true global minimizer.<br />
An alternative method is to determine the critical points of an objective function on the model.<br />
In algebraic statistics, the models of interest are algebraic sets, i.e., solution sets to a system of multivariate polynomial equations. In this situation, the number of critical points of the squared Euclidean distance function on the model’s Zariski closure is a topological invariant called the Euclidean distance degree (ED degree).<br />
In this talk, I will present some models from computer vision and statistics that may be described as algebraic sets. Moreover,<br />
I will describe a topological method for determining a Euclidean distance degree and a numerical algebraic geometry approach for<br />
determining critical points of the squared Euclidean distance function.<br />
<br />
<br />
===Ananth Shankar (MIT)===<br />
<br />
Abstract: An abelian surface 'splits' if it admits a non-trivial map to some elliptic curve. It is well known that the set of abelian surfaces that split are sparse in the set of all abelian surfaces. Nevertheless, we prove that there are infinitely many split abelian surfaces in arithmetic one-parameter families of generically non-split abelian surfaces. I will describe this work, and if time permits, mention generalizations of this result to the setting of K3 surfaces, as well as applications to the dynamics of hecke orbits. This is joint work with Tang, Maulik-Tang, and Shankar-Tang-Tayou.<br />
<br />
<br />
===Franca Hoffman (Caltech)===<br />
<br />
Title: Gradient Flows: From PDE to Data Analysis.<br />
<br />
Abstract: Certain diffusive PDEs can be viewed as infinite-dimensional gradient flows. This fact has led to the development of new tools in various areas of mathematics ranging from PDE theory to data science. In this talk, we focus on two different directions: model-driven approaches and data-driven approaches.<br />
In the first part of the talk we use gradient flows for analyzing non-linear and non-local aggregation-diffusion equations when the corresponding energy functionals are not necessarily convex. Moreover, the gradient flow structure enables us to make connections to well-known functional inequalities, revealing possible links between the optimizers of these inequalities and the equilibria of certain aggregation-diffusion PDEs.<br />
In the second part, we use and develop gradient flow theory to design novel tools for data analysis. We draw a connection between gradient flows and Ensemble Kalman methods for parameter estimation. We introduce the Ensemble Kalman Sampler - a derivative-free methodology for model calibration and uncertainty quantification in expensive black-box models. The interacting particle dynamics underlying our algorithm can be approximated by a novel gradient flow structure in a modified Wasserstein metric which reflects particle correlations. The geometry of this modified Wasserstein metric is of independent theoretical interest.<br />
<br />
<br />
=== Jeffrey Danciger (UT Austin) ===<br />
<br />
Title: Affine geometry and the Auslander Conjecture<br />
<br />
Abstract: The Auslander Conjecture is an analogue of Bieberbach’s theory of Euclidean crystallographic groups in the setting of affine geometry. It predicts that a complete affine manifold (a manifold equipped with a complete torsion-free flat affine connection) which is compact must have virtually solvable fundamental group. The conjecture is known up to dimension six, but is known to fail if the compactness assumption is removed, even in low dimensions. We discuss some history of this conjecture, give some basic examples, and then survey some recent advances in the study of non-compact complete affine manifolds with non-solvable fundamental group. <br />
Tools from the deformation theory of pseudo-Riemannian hyperbolic manifolds and also from higher Teichm&uuml;ller theory will enter the picture.<br />
<br />
<br />
=== Tatyana Shcherbina (Princeton) ===<br />
<br />
Title: Random matrix theory and supersymmetry techniques<br />
<br />
Abstract: Starting from the works of Erdos, Yau, Schlein with coauthors, the significant progress in understanding the universal behavior of many random graph and random matrix models were achieved. However for the random matrices with a special structure our understanding is still very limited. In this talk I am going to overview applications of another approach to the study of the local eigenvalues statistics in random matrix theory based on so-called supersymmetry techniques (SUSY). SUSY approach is based on the representation of the determinant as an integral over the Grassmann (anticommuting) variables. Combining this representation with the representation of an inverse determinant as an integral over the Gaussian complex field, SUSY allows to obtain an integral representation for the main spectral characteristics of random matrices such as limiting density, correlation functions, the resolvent's elements, etc. This method is widely (and successfully) used in the physics literature and is potentially very powerful but the rigorous control of the integral representations, which can be obtained by this method, is quite difficult, and it requires powerful analytic and statistical mechanics tools. In this talk we will discuss some recent progress in application of SUSY to the analysis of local spectral characteristics of the prominent ensemble of random band matrices, i.e. random matrices<br />
whose entries become negligible if their distance from the main diagonal exceeds a certain parameter called the band width. <br />
<br />
<br />
=== Tingran Gao (University of Chicago) ===<br />
<br />
Title: Manifold Learning on Fibre Bundles<br />
<br />
Abstract: Spectral geometry has played an important role in modern geometric data analysis, where the technique is widely known as Laplacian eigenmaps or diffusion maps. In this talk, we present a geometric framework that studies graph representations of complex datasets, where each edge of the graph is equipped with a non-scalar transformation or correspondence. This new framework models such a dataset as a fibre bundle with a connection, and interprets the collection of pairwise functional relations as defining a horizontal diffusion process on the bundle driven by its projection on the base. The eigenstates of this horizontal diffusion process encode the “consistency” among objects in the dataset, and provide a lens through which the geometry of the dataset can be revealed. We demonstrate an application of this geometric framework on evolutionary anthropology.<br />
<br />
<br />
=== Andrew Zimmer (LSU) ===<br />
<br />
Title: Intrinsic and extrinsic geometries in several complex variables<br />
<br />
Abstract: A bounded domain in complex Euclidean space, despite being one of the simplest types of manifolds, has a number of interesting geometric structures. When the domain is pseudoconvex, it has a natural intrinsic geometry: the complete Kaehler-Einstein metric constructed by Cheng-Yau and Mok-Yau. When the domain is smoothly bounded, there is also a natural extrinsic structure: the CR-geometry of the boundary. In this talk, I will describe connections between these intrinsic and extrinsic geometries. Then, I will discuss how these connections can lead to new analytic results.<br />
<br />
<br />
=== Hui Yu (Columbia) ===<br />
<br />
Title: Singular sets in obstacle problems<br />
<br />
Abstract: One of the most important free boundary problems is the obstacle problem. The regularity of its free boundary has been studied for over half a century. In this talk, we review some classical results as well as exciting new developments. In particular, we discuss the recent resolution of the regularity of the singular set for the fully nonlinear obstacle problem. This talk is based on a joint work with Ovidiu Savin at Columbia University.<br />
<br />
<br />
=== Nick Higham (Manchester) ===<br />
<br />
Title: Challenges in Multivalued Matrix Functions<br />
<br />
Abstract: In this lecture I will discuss multivalued matrix functions that arise in solving various kinds of matrix equations. The matrix logarithm is the prototypical example, and my first interaction with Hans Schneider was about this function. Another example is the Lambert W function of a matrix, which is much less well known but has been attracting recent interest. A theme of the talk is the importance of choosing appropriate principal values and making sure that the correct choices of signs and branches are used,<br />
both in theory and in computation. I will give examples where incorrect results have previously been obtained.<br />
<br />
I focus on matrix inverse trigonometric and inverse hyperbolic functions, beginning by investigating existence and characterization. Turning to the principal values, various functional identities are derived, some of which are new even in the scalar case, including a “round trip” formula that relates acos(cos A) to A and similar formulas for the other inverse functions. Key tools used in the derivations are the matrix unwinding function and the matrix sign function.<br />
<br />
A new inverse scaling and squaring type algorithm employing a Schur decomposition and variable-degree Pade approximation is derived for computing acos, and it is shown how it can also be used to compute asin, acosh, and asinh.<br />
<br />
== Future Colloquia ==<br />
[[Colloquia/Fall 2020| Fall 2020]]<br />
<br />
== Past Colloquia ==<br />
<br />
[[Colloquia/Blank|Blank]]<br />
<br />
[[Colloquia/Spring2019|Spring 2019]]<br />
<br />
[[Colloquia/Fall2018|Fall 2018]]<br />
<br />
[[Colloquia/Spring2018|Spring 2018]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Colloquia&diff=18501Colloquia2019-11-28T19:00:49Z<p>Jeanluc: /* Mathematics Colloquium */</p>
<hr />
<div>= Mathematics Colloquium =<br />
<br />
All colloquia are on Fridays at 4:00 pm in Van Vleck B239, '''unless otherwise indicated'''.<br />
<br />
<br />
<br />
==Fall 2019==<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|Sept 6 '''Room 911'''<br />
| Will Sawin (Columbia)<br />
| [[#Will Sawin (Columbia) | On Chowla's Conjecture over F_q[T] ]]<br />
| Marshall<br />
|-<br />
|Sept 13<br />
| [https://www.math.ksu.edu/~soibel/ Yan Soibelman] (Kansas State)<br />
|[[#Yan Soibelman (Kansas State)| Riemann-Hilbert correspondence and Fukaya categories ]]<br />
| Caldararu<br />
|<br />
|-<br />
|Sept 16 '''Monday Room 911'''<br />
| [http://mate.dm.uba.ar/~alidick/ Alicia Dickenstein] (Buenos Aires)<br />
|[[#Alicia Dickenstein (Buenos Aires)| Algebra and geometry in the study of enzymatic cascades ]]<br />
| Craciun<br />
|<br />
|-<br />
|Sept 20<br />
| [https://math.duke.edu/~jianfeng/ Jianfeng Lu] (Duke)<br />
|[[#Jianfeng Lu (Duke) | How to "localize" the computation?]]<br />
| Qin<br />
|<br />
|-<br />
|Sept 26 '''Thursday 3-4 pm Room 911'''<br />
| [http://eugeniacheng.com/ Eugenia Cheng] (School of the Art Institute of Chicago)<br />
| [[#Eugenia Cheng (School of the Art Institute of Chicago)| Character vs gender in mathematics and beyond ]]<br />
| Marshall / Friends of UW Madison Libraries<br />
|<br />
|-<br />
|Sept 27<br />
|<br />
|<br />
|-<br />
|Oct 4<br />
|<br />
|<br />
|-<br />
|Oct 11<br />
| Omer Mermelstein (Madison)<br />
| [[#Omer Mermelstein (Madison)| Generic flat pregeometries ]]<br />
|Andrews<br />
|<br />
|-<br />
|Oct 18<br />
| Shamgar Gurevich (Madison)<br />
| [[#Shamgar Gurevich (Madison) | Harmonic Analysis on GL(n) over Finite Fields ]]<br />
| Marshall<br />
|-<br />
|Oct 25<br />
|<br />
|-<br />
|Nov 1<br />
|Elchanan Mossel (MIT)<br />
|Distinguished Lecture<br />
|Roch<br />
|-<br />
|Nov 8<br />
|Jose Rodriguez (UW-Madison)<br />
|[[#Jose Rodriguez (UW-Madison) | Nearest Point Problems and Euclidean Distance Degrees]]<br />
|Erman<br />
|-<br />
|Nov 13 '''Wednesday 4-5pm'''<br />
|Ananth Shankar (MIT)<br />
|Exceptional splitting of abelian surfaces<br />
|-<br />
|Nov 20 '''Wednesday 4-5pm'''<br />
|Franca Hoffman (Caltech)<br />
|[[#Franca Hoffman (Caltech) | Gradient Flows: From PDE to Data Analysis]]<br />
|Smith<br />
|-<br />
|Nov 22<br />
| Jeffrey Danciger (UT Austin)<br />
| [[#Jeffrey Danciger (UT Austin) | "Affine geometry and the Auslander Conjecture"]]<br />
| Kent<br />
|-<br />
|Nov 25 '''Monday 4-5 pm Room 911'''<br />
|Tatyana Shcherbina (Princeton)<br />
| [[# Tatyana Shcherbina (Princeton)| "Random matrix theory and supersymmetry techniques"]]<br />
|Roch<br />
|-<br />
|Nov 29<br />
|Thanksgiving<br />
|<br />
|-<br />
|Dec 2 '''Monday 4-5pm'''<br />
|Tingran Gao (University of Chicago)<br />
| [[#Tingran Gao (University of Chicago)| "Manifold Learning on Fibre Bundles"]]<br />
|Smith<br />
|-<br />
|Dec 4 '''Wednesday 4-5 pm'''<br />
|Andrew Zimmer<br />
| Intrinsic and extrinsic geometries in several complex variables<br />
|Gong<br />
|-<br />
|Dec 6<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Dec 9 '''Monday 4-5 pm'''<br />
|Hui Yu (Columbia)<br />
|[[#Hui Yu (Columbia)|Singular sets in obstacle problems]]<br />
|Tran<br />
|-<br />
|Dec 11 '''Wednesday'''<br />
|Nick Higham (Manchester)<br />
|[[#Nick Higham (Manchester)|LAA lecture: Challenges in Multivalued Matrix Functions]]<br />
|Brualdi<br />
|<br />
|-<br />
|Dec 13<br />
|Reserved for job talk<br />
|<br />
|}<br />
<br />
==Spring 2020==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|<br />
|-<br />
|Jan 24<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Jan 29 '''Wednesday 4-5 pm'''<br />
|[https://ajzucker.wordpress.com/ Andy Zucker] (Lyon)<br />
|<br />
|Soskova/Lempp<br />
|<br />
|-<br />
|Jan 31<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Feb 7<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Feb 14<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Feb 21<br />
|Shai Evra (IAS)<br />
|<br />
|Gurevich<br />
|<br />
|-<br />
|Feb 28<br />
|Brett Wick (Washington University, St. Louis)<br />
|<br />
|Seeger<br />
|-<br />
|March 6<br />
| Jessica Fintzen (Michigan)<br />
|<br />
|Marshall<br />
|-<br />
|March 13<br />
|<br />
|-<br />
|March 20<br />
|Spring break<br />
|<br />
|-<br />
|March 27<br />
|(Moduli Spaces Conference)<br />
|<br />
|Boggess, Sankar<br />
|-<br />
|April 3<br />
|Caroline Turnage-Butterbaugh (Carleton College)<br />
|<br />
|Marshall<br />
|-<br />
|April 10<br />
| Sarah Koch (Michigan)<br />
|<br />
| Bruce (WIMAW)<br />
|-<br />
|April 17<br />
|Song Sun (Berkeley)<br />
|<br />
|Huang<br />
|-<br />
|April 24<br />
|Natasa Sesum (Rutgers University)<br />
|<br />
|Angenent<br />
|-<br />
|May 1<br />
|Robert Lazarsfeld (Stony Brook)<br />
|Distinguished lecture<br />
|Erman<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
<br />
===Will Sawin (Columbia)===<br />
<br />
Title: On Chowla's Conjecture over F_q[T]<br />
<br />
Abstract: The Mobius function in number theory is a sequences of 1s, <br />
-1s, and 0s, which is simple to define and closely related to the <br />
prime numbers. Its behavior seems highly random. Chowla's conjecture <br />
is one precise formalization of this randomness, and has seen recent <br />
work by Matomaki, Radziwill, Tao, and Teravainen making progress on <br />
it. In joint work with Mark Shusterman, we modify this conjecture by <br />
replacing the natural numbers parameterizing this sequence with <br />
polynomials over a finite field. Under mild conditions on the finite <br />
field, we are able to prove a strong form of this conjecture. The <br />
proof is based on taking a geometric perspective on the problem, and <br />
succeeds because we are able to simplify the geometry using a trick <br />
based on the strange properties of polynomial derivatives over finite <br />
fields.<br />
<br />
<br />
===Yan Soibelman (Kansas State)===<br />
<br />
Title: Riemann-Hilbert correspondence and Fukaya categories<br />
<br />
Abstract: In this talk I am going to discuss the role of Fukaya categories in the Riemann-Hilbert correspondence<br />
for differential, q-difference and elliptic difference equations in dimension one.<br />
This approach not only gives a unified answer for several versions of the Riemann-Hilbert correspondence but also leads to a natural formulation<br />
of the non-abelian Hodge theory in dimension one. It also explains why periodic monopoles<br />
should appear as harmonic objects in this generalized non-abelian Hodge theory.<br />
All that is a part of the bigger project ``Holomorphic Floer theory",<br />
joint with Maxim Kontsevich.<br />
<br />
<br />
===Alicia Dickenstein (Buenos Aires)===<br />
<br />
Title: Algebra and geometry in the study of enzymatic cascades<br />
<br />
Abstract: In recent years, techniques from computational and real algebraic geometry have been successfully used to address mathematical challenges in systems biology. The algebraic theory of chemical reaction systems aims to understand their dynamic behavior by taking advantage of the inherent algebraic structure in the kinetic equations, and does not need the determination of the parameters a priori, which can be theoretically or practically impossible.<br />
I will give a gentle introduction to general results based on the network structure. In particular, I will describe a general framework for biological systems, called MESSI systems, that describe Modifications of type Enzyme-Substrate or Swap with Intermediates, and include many networks that model post-translational modifications of proteins inside the cell. I will also outline recent methods to address the important question of multistationarity, in particular in the study of enzymatic cascades, and will point out some of the mathematical challenges that arise from this application.<br />
<br />
<br />
=== Jianfeng Lu (Duke) ===<br />
Title: How to ``localize" the computation?<br />
<br />
It is often desirable to restrict the numerical computation to a local region to achieve best balance between accuracy and affordability in scientific computing. It is important to avoid artifacts and guarantee predictable modelling while artificial boundary conditions have to be introduced to restrict the computation. In this talk, we will discuss some recent understanding on how to achieve such local computation in the context of topological edge states and elliptic random media.<br />
<br />
<br />
===Eugenia Cheng (School of the Art Institute of Chicago)===<br />
<br />
Title: Character vs gender in mathematics and beyond<br />
<br />
Abstract: This presentation will be based on my experience of being a female mathematician, and teaching mathematics at all levels from elementary school to grad school. The question of why women are under-represented in mathematics is complex and there are no simple answers, only many many contributing factors. I will focus on character traits, and argue that if we focus on this rather than gender we can have a more productive and less divisive conversation. To try and focus on characters rather than genders I will introduce gender-neutral character adjectives "ingressive" and "congressive" to replace masculine and feminine. I will share my experience of teaching congressive abstract mathematics to art students, in a congressive way, and the possible effects this could have for everyone in mathematics, not just women.<br />
<br />
<br />
===Omer Mermelstein (Madison)===<br />
<br />
Title: Generic flat pregeometries<br />
<br />
Abstract: In model theory, the tamest of structures are the strongly minimal ones -- those in which every equation in a single variable has either finitely many or cofinitely many solution. Algebraically closed fields and vector spaces are the canonical examples. Zilber’s conjecture, later refuted by Hrushovski, states that the source of geometric complexity in a strongly minimal structure must be algebraic. The property of "flatness" (strict gammoid) of a geometry (matroid) is that which guarantees Hrushovski's construction is devoid of any associative structure.<br />
The majority of the talk will explain what flatness is, how it should be thought of, and how closely it relates to hypergraphs and Hrushovski's construction method. Model theory makes an appearance only in the second part, where I will share results pertaining to the specific family of geometries arising from Hrushovski's methods.<br />
<br />
<br />
===Shamgar Gurevich (Madison)===<br />
<br />
Title: Harmonic Analysis on GL(n) over Finite Fields.<br />
<br />
Abstract: There are many formulas that express interesting properties of a finite group G in terms of sums over its characters. For evaluating or estimating these sums, one of the most salient quantities to understand is the character ratio:<br />
<br />
trace(ρ(g)) / dim(ρ),<br />
<br />
for an irreducible representation ρ of G and an element g of G. For example, Diaconis and Shahshahani stated a formula of the mentioned type for analyzing certain random walks on G.<br />
<br />
Recently, we discovered that for classical groups G over finite fields there is a natural invariant of representations that provides strong information on the character ratio. We call this invariant rank. <br />
<br />
This talk will discuss the notion of rank for the group GLn over finite fields, demonstrate how it controls the character ratio, and explain how one can apply the results to verify mixing time and rate for certain random walks.<br />
<br />
This is joint work with Roger Howe (Yale and Texas AM). The numerics for this work was carried by Steve Goldstein (Madison)<br />
<br />
<br />
===Jose Rodriguez (UW-Madison)===<br />
<br />
Abstract: Determining the closest point to a model (subset of Euclidean space) is an important problem in many applications in science,<br />
engineering, and statistics. One way to solve this problem is by minimizing the squared Euclidean distance function using a gradient<br />
descent approach. However, when there are multiple local minima, there is no guarantee of convergence to the true global minimizer.<br />
An alternative method is to determine the critical points of an objective function on the model.<br />
In algebraic statistics, the models of interest are algebraic sets, i.e., solution sets to a system of multivariate polynomial equations. In this situation, the number of critical points of the squared Euclidean distance function on the model’s Zariski closure is a topological invariant called the Euclidean distance degree (ED degree).<br />
In this talk, I will present some models from computer vision and statistics that may be described as algebraic sets. Moreover,<br />
I will describe a topological method for determining a Euclidean distance degree and a numerical algebraic geometry approach for<br />
determining critical points of the squared Euclidean distance function.<br />
<br />
<br />
===Ananth Shankar (MIT)===<br />
<br />
Abstract: An abelian surface 'splits' if it admits a non-trivial map to some elliptic curve. It is well known that the set of abelian surfaces that split are sparse in the set of all abelian surfaces. Nevertheless, we prove that there are infinitely many split abelian surfaces in arithmetic one-parameter families of generically non-split abelian surfaces. I will describe this work, and if time permits, mention generalizations of this result to the setting of K3 surfaces, as well as applications to the dynamics of hecke orbits. This is joint work with Tang, Maulik-Tang, and Shankar-Tang-Tayou.<br />
<br />
<br />
===Franca Hoffman (Caltech)===<br />
<br />
Title: Gradient Flows: From PDE to Data Analysis.<br />
<br />
Abstract: Certain diffusive PDEs can be viewed as infinite-dimensional gradient flows. This fact has led to the development of new tools in various areas of mathematics ranging from PDE theory to data science. In this talk, we focus on two different directions: model-driven approaches and data-driven approaches.<br />
In the first part of the talk we use gradient flows for analyzing non-linear and non-local aggregation-diffusion equations when the corresponding energy functionals are not necessarily convex. Moreover, the gradient flow structure enables us to make connections to well-known functional inequalities, revealing possible links between the optimizers of these inequalities and the equilibria of certain aggregation-diffusion PDEs.<br />
In the second part, we use and develop gradient flow theory to design novel tools for data analysis. We draw a connection between gradient flows and Ensemble Kalman methods for parameter estimation. We introduce the Ensemble Kalman Sampler - a derivative-free methodology for model calibration and uncertainty quantification in expensive black-box models. The interacting particle dynamics underlying our algorithm can be approximated by a novel gradient flow structure in a modified Wasserstein metric which reflects particle correlations. The geometry of this modified Wasserstein metric is of independent theoretical interest.<br />
<br />
<br />
=== Jeffrey Danciger (UT Austin) ===<br />
<br />
Title: Affine geometry and the Auslander Conjecture<br />
<br />
Abstract: The Auslander Conjecture is an analogue of Bieberbach’s theory of Euclidean crystallographic groups in the setting of affine geometry. It predicts that a complete affine manifold (a manifold equipped with a complete torsion-free flat affine connection) which is compact must have virtually solvable fundamental group. The conjecture is known up to dimension six, but is known to fail if the compactness assumption is removed, even in low dimensions. We discuss some history of this conjecture, give some basic examples, and then survey some recent advances in the study of non-compact complete affine manifolds with non-solvable fundamental group. <br />
Tools from the deformation theory of pseudo-Riemannian hyperbolic manifolds and also from higher Teichm&uuml;ller theory will enter the picture.<br />
<br />
<br />
=== Tatyana Shcherbina (Princeton) ===<br />
<br />
Title: Random matrix theory and supersymmetry techniques<br />
<br />
Abstract: Starting from the works of Erdos, Yau, Schlein with coauthors, the significant progress in understanding the universal behavior of many random graph and random matrix models were achieved. However for the random matrices with a special structure our understanding is still very limited. In this talk I am going to overview applications of another approach to the study of the local eigenvalues statistics in random matrix theory based on so-called supersymmetry techniques (SUSY). SUSY approach is based on the representation of the determinant as an integral over the Grassmann (anticommuting) variables. Combining this representation with the representation of an inverse determinant as an integral over the Gaussian complex field, SUSY allows to obtain an integral representation for the main spectral characteristics of random matrices such as limiting density, correlation functions, the resolvent's elements, etc. This method is widely (and successfully) used in the physics literature and is potentially very powerful but the rigorous control of the integral representations, which can be obtained by this method, is quite difficult, and it requires powerful analytic and statistical mechanics tools. In this talk we will discuss some recent progress in application of SUSY to the analysis of local spectral characteristics of the prominent ensemble of random band matrices, i.e. random matrices<br />
whose entries become negligible if their distance from the main diagonal exceeds a certain parameter called the band width. <br />
<br />
<br />
=== Tingran Gao (University of Chicago) ===<br />
<br />
Title: Manifold Learning on Fibre Bundles<br />
<br />
Abstract: Spectral geometry has played an important role in modern geometric data analysis, where the technique is widely known as Laplacian eigenmaps or diffusion maps. In this talk, we present a geometric framework that studies graph representations of complex datasets, where each edge of the graph is equipped with a non-scalar transformation or correspondence. This new framework models such a dataset as a fibre bundle with a connection, and interprets the collection of pairwise functional relations as defining a horizontal diffusion process on the bundle driven by its projection on the base. The eigenstates of this horizontal diffusion process encode the “consistency” among objects in the dataset, and provide a lens through which the geometry of the dataset can be revealed. We demonstrate an application of this geometric framework on evolutionary anthropology.<br />
<br />
<br />
=== Andrew Zimmer (LSU) ===<br />
<br />
Title: Intrinsic and extrinsic geometries in several complex variables<br />
<br />
Abstract: A bounded domain in complex Euclidean space, despite being one of the simplest types of manifolds, has a number of interesting geometric structures. When the domain is pseudoconvex, it has a natural intrinsic geometry: the complete Kaehler-Einstein metric constructed by Cheng-Yau and Mok-Yau. When the domain is smoothly bounded, there is also a natural extrinsic structure: the CR-geometry of the boundary. In this talk, I will describe connections between these intrinsic and extrinsic geometries. Then, I will discuss how these connections can lead to new analytic results.<br />
<br />
<br />
=== Nick Higham (Manchester) ===<br />
<br />
Title: Challenges in Multivalued Matrix Functions<br />
<br />
Abstract: In this lecture I will discuss multivalued matrix functions that arise in solving various kinds of matrix equations. The matrix logarithm is the prototypical example, and my first interaction with Hans Schneider was about this function. Another example is the Lambert W function of a matrix, which is much less well known but has been attracting recent interest. A theme of the talk is the importance of choosing appropriate principal values and making sure that the correct choices of signs and branches are used,<br />
both in theory and in computation. I will give examples where incorrect results have previously been obtained.<br />
<br />
I focus on matrix inverse trigonometric and inverse hyperbolic functions, beginning by investigating existence and characterization. Turning to the principal values, various functional identities are derived, some of which are new even in the scalar case, including a “round trip” formula that relates acos(cos A) to A and similar formulas for the other inverse functions. Key tools used in the derivations are the matrix unwinding function and the matrix sign function.<br />
<br />
A new inverse scaling and squaring type algorithm employing a Schur decomposition and variable-degree Pade approximation is derived for computing acos, and it is shown how it can also be used to compute asin, acosh, and asinh.<br />
<br />
<br />
=== Hui Yu (Columbia) ===<br />
<br />
Title: Singular sets in obstacle problems<br />
<br />
Abstract: One of the most important free boundary problems is the obstacle problem. The regularity of its free boundary has been studied for over half a century. In this talk, we review some classical results as well as exciting new developments. In particular, we discuss the recent resolution of the regularity of the singular set for the fully nonlinear obstacle problem. This talk is based on a joint work with Ovidiu Savin at Columbia University.<br />
<br />
== Future Colloquia ==<br />
[[Colloquia/Fall 2020| Fall 2020]]<br />
<br />
== Past Colloquia ==<br />
<br />
[[Colloquia/Blank|Blank]]<br />
<br />
[[Colloquia/Spring2019|Spring 2019]]<br />
<br />
[[Colloquia/Fall2018|Fall 2018]]<br />
<br />
[[Colloquia/Spring2018|Spring 2018]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Colloquia&diff=18500Colloquia2019-11-28T18:58:45Z<p>Jeanluc: /* Abstracts */</p>
<hr />
<div>= Mathematics Colloquium =<br />
<br />
All colloquia are on Fridays at 4:00 pm in Van Vleck B239, '''unless otherwise indicated'''.<br />
<br />
<br />
<br />
==Fall 2019==<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|Sept 6 '''Room 911'''<br />
| Will Sawin (Columbia)<br />
| [[#Will Sawin (Columbia) | On Chowla's Conjecture over F_q[T] ]]<br />
| Marshall<br />
|-<br />
|Sept 13<br />
| [https://www.math.ksu.edu/~soibel/ Yan Soibelman] (Kansas State)<br />
|[[#Yan Soibelman (Kansas State)| Riemann-Hilbert correspondence and Fukaya categories ]]<br />
| Caldararu<br />
|<br />
|-<br />
|Sept 16 '''Monday Room 911'''<br />
| [http://mate.dm.uba.ar/~alidick/ Alicia Dickenstein] (Buenos Aires)<br />
|[[#Alicia Dickenstein (Buenos Aires)| Algebra and geometry in the study of enzymatic cascades ]]<br />
| Craciun<br />
|<br />
|-<br />
|Sept 20<br />
| [https://math.duke.edu/~jianfeng/ Jianfeng Lu] (Duke)<br />
|[[#Jianfeng Lu (Duke) | How to "localize" the computation?]]<br />
| Qin<br />
|<br />
|-<br />
|Sept 26 '''Thursday 3-4 pm Room 911'''<br />
| [http://eugeniacheng.com/ Eugenia Cheng] (School of the Art Institute of Chicago)<br />
| [[#Eugenia Cheng (School of the Art Institute of Chicago)| Character vs gender in mathematics and beyond ]]<br />
| Marshall / Friends of UW Madison Libraries<br />
|<br />
|-<br />
|Sept 27<br />
|<br />
|<br />
|-<br />
|Oct 4<br />
|<br />
|<br />
|-<br />
|Oct 11<br />
| Omer Mermelstein (Madison)<br />
| [[#Omer Mermelstein (Madison)| Generic flat pregeometries ]]<br />
|Andrews<br />
|<br />
|-<br />
|Oct 18<br />
| Shamgar Gurevich (Madison)<br />
| [[#Shamgar Gurevich (Madison) | Harmonic Analysis on GL(n) over Finite Fields ]]<br />
| Marshall<br />
|-<br />
|Oct 25<br />
|<br />
|-<br />
|Nov 1<br />
|Elchanan Mossel (MIT)<br />
|Distinguished Lecture<br />
|Roch<br />
|-<br />
|Nov 8<br />
|Jose Rodriguez (UW-Madison)<br />
|[[#Jose Rodriguez (UW-Madison) | Nearest Point Problems and Euclidean Distance Degrees]]<br />
|Erman<br />
|-<br />
|Nov 13 '''Wednesday 4-5pm'''<br />
|Ananth Shankar (MIT)<br />
|Exceptional splitting of abelian surfaces<br />
|-<br />
|Nov 20 '''Wednesday 4-5pm'''<br />
|Franca Hoffman (Caltech)<br />
|[[#Franca Hoffman (Caltech) | Gradient Flows: From PDE to Data Analysis]]<br />
|Smith<br />
|-<br />
|Nov 22<br />
| Jeffrey Danciger (UT Austin)<br />
| [[#Jeffrey Danciger (UT Austin) | "Affine geometry and the Auslander Conjecture"]]<br />
| Kent<br />
|-<br />
|Nov 25 '''Monday 4-5 pm Room 911'''<br />
|Tatyana Shcherbina (Princeton)<br />
| [[# Tatyana Shcherbina (Princeton)| "Random matrix theory and supersymmetry techniques"]]<br />
|Roch<br />
|-<br />
|Nov 29<br />
|Thanksgiving<br />
|<br />
|-<br />
|Dec 2 '''Monday 4-5pm'''<br />
|Tingran Gao (University of Chicago)<br />
| [[#Tingran Gao (University of Chicago)| "Manifold Learning on Fibre Bundles"]]<br />
|Smith<br />
|-<br />
|Dec 4 '''Wednesday 4-5 pm'''<br />
|Andrew Zimmer<br />
| Intrinsic and extrinsic geometries in several complex variables<br />
|Gong<br />
|-<br />
|Dec 6<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Dec 9 '''Monday 4-5 pm'''<br />
|Hui Yu (Columbia)<br />
| [[#Hui Yu (Columbia)| Singular sets in obstacle problems]]<br />
|Tran<br />
|-<br />
|Dec 11 '''Wednesday'''<br />
|Nick Higham (Manchester)<br />
|LAA lecture<br />
|Brualdi<br />
|<br />
|-<br />
|Dec 13<br />
|Reserved for job talk<br />
|<br />
|}<br />
<br />
==Spring 2020==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|<br />
|-<br />
|Jan 24<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Jan 29 '''Wednesday 4-5 pm'''<br />
|[https://ajzucker.wordpress.com/ Andy Zucker] (Lyon)<br />
|<br />
|Soskova/Lempp<br />
|<br />
|-<br />
|Jan 31<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Feb 7<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Feb 14<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Feb 21<br />
|Shai Evra (IAS)<br />
|<br />
|Gurevich<br />
|<br />
|-<br />
|Feb 28<br />
|Brett Wick (Washington University, St. Louis)<br />
|<br />
|Seeger<br />
|-<br />
|March 6<br />
| Jessica Fintzen (Michigan)<br />
|<br />
|Marshall<br />
|-<br />
|March 13<br />
|<br />
|-<br />
|March 20<br />
|Spring break<br />
|<br />
|-<br />
|March 27<br />
|(Moduli Spaces Conference)<br />
|<br />
|Boggess, Sankar<br />
|-<br />
|April 3<br />
|Caroline Turnage-Butterbaugh (Carleton College)<br />
|<br />
|Marshall<br />
|-<br />
|April 10<br />
| Sarah Koch (Michigan)<br />
|<br />
| Bruce (WIMAW)<br />
|-<br />
|April 17<br />
|Song Sun (Berkeley)<br />
|<br />
|Huang<br />
|-<br />
|April 24<br />
|Natasa Sesum (Rutgers University)<br />
|<br />
|Angenent<br />
|-<br />
|May 1<br />
|Robert Lazarsfeld (Stony Brook)<br />
|Distinguished lecture<br />
|Erman<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
<br />
===Will Sawin (Columbia)===<br />
<br />
Title: On Chowla's Conjecture over F_q[T]<br />
<br />
Abstract: The Mobius function in number theory is a sequences of 1s, <br />
-1s, and 0s, which is simple to define and closely related to the <br />
prime numbers. Its behavior seems highly random. Chowla's conjecture <br />
is one precise formalization of this randomness, and has seen recent <br />
work by Matomaki, Radziwill, Tao, and Teravainen making progress on <br />
it. In joint work with Mark Shusterman, we modify this conjecture by <br />
replacing the natural numbers parameterizing this sequence with <br />
polynomials over a finite field. Under mild conditions on the finite <br />
field, we are able to prove a strong form of this conjecture. The <br />
proof is based on taking a geometric perspective on the problem, and <br />
succeeds because we are able to simplify the geometry using a trick <br />
based on the strange properties of polynomial derivatives over finite <br />
fields.<br />
<br />
<br />
===Yan Soibelman (Kansas State)===<br />
<br />
Title: Riemann-Hilbert correspondence and Fukaya categories<br />
<br />
Abstract: In this talk I am going to discuss the role of Fukaya categories in the Riemann-Hilbert correspondence<br />
for differential, q-difference and elliptic difference equations in dimension one.<br />
This approach not only gives a unified answer for several versions of the Riemann-Hilbert correspondence but also leads to a natural formulation<br />
of the non-abelian Hodge theory in dimension one. It also explains why periodic monopoles<br />
should appear as harmonic objects in this generalized non-abelian Hodge theory.<br />
All that is a part of the bigger project ``Holomorphic Floer theory",<br />
joint with Maxim Kontsevich.<br />
<br />
<br />
===Alicia Dickenstein (Buenos Aires)===<br />
<br />
Title: Algebra and geometry in the study of enzymatic cascades<br />
<br />
Abstract: In recent years, techniques from computational and real algebraic geometry have been successfully used to address mathematical challenges in systems biology. The algebraic theory of chemical reaction systems aims to understand their dynamic behavior by taking advantage of the inherent algebraic structure in the kinetic equations, and does not need the determination of the parameters a priori, which can be theoretically or practically impossible.<br />
I will give a gentle introduction to general results based on the network structure. In particular, I will describe a general framework for biological systems, called MESSI systems, that describe Modifications of type Enzyme-Substrate or Swap with Intermediates, and include many networks that model post-translational modifications of proteins inside the cell. I will also outline recent methods to address the important question of multistationarity, in particular in the study of enzymatic cascades, and will point out some of the mathematical challenges that arise from this application.<br />
<br />
<br />
=== Jianfeng Lu (Duke) ===<br />
Title: How to ``localize" the computation?<br />
<br />
It is often desirable to restrict the numerical computation to a local region to achieve best balance between accuracy and affordability in scientific computing. It is important to avoid artifacts and guarantee predictable modelling while artificial boundary conditions have to be introduced to restrict the computation. In this talk, we will discuss some recent understanding on how to achieve such local computation in the context of topological edge states and elliptic random media.<br />
<br />
<br />
===Eugenia Cheng (School of the Art Institute of Chicago)===<br />
<br />
Title: Character vs gender in mathematics and beyond<br />
<br />
Abstract: This presentation will be based on my experience of being a female mathematician, and teaching mathematics at all levels from elementary school to grad school. The question of why women are under-represented in mathematics is complex and there are no simple answers, only many many contributing factors. I will focus on character traits, and argue that if we focus on this rather than gender we can have a more productive and less divisive conversation. To try and focus on characters rather than genders I will introduce gender-neutral character adjectives "ingressive" and "congressive" to replace masculine and feminine. I will share my experience of teaching congressive abstract mathematics to art students, in a congressive way, and the possible effects this could have for everyone in mathematics, not just women.<br />
<br />
<br />
===Omer Mermelstein (Madison)===<br />
<br />
Title: Generic flat pregeometries<br />
<br />
Abstract: In model theory, the tamest of structures are the strongly minimal ones -- those in which every equation in a single variable has either finitely many or cofinitely many solution. Algebraically closed fields and vector spaces are the canonical examples. Zilber’s conjecture, later refuted by Hrushovski, states that the source of geometric complexity in a strongly minimal structure must be algebraic. The property of "flatness" (strict gammoid) of a geometry (matroid) is that which guarantees Hrushovski's construction is devoid of any associative structure.<br />
The majority of the talk will explain what flatness is, how it should be thought of, and how closely it relates to hypergraphs and Hrushovski's construction method. Model theory makes an appearance only in the second part, where I will share results pertaining to the specific family of geometries arising from Hrushovski's methods.<br />
<br />
<br />
===Shamgar Gurevich (Madison)===<br />
<br />
Title: Harmonic Analysis on GL(n) over Finite Fields.<br />
<br />
Abstract: There are many formulas that express interesting properties of a finite group G in terms of sums over its characters. For evaluating or estimating these sums, one of the most salient quantities to understand is the character ratio:<br />
<br />
trace(ρ(g)) / dim(ρ),<br />
<br />
for an irreducible representation ρ of G and an element g of G. For example, Diaconis and Shahshahani stated a formula of the mentioned type for analyzing certain random walks on G.<br />
<br />
Recently, we discovered that for classical groups G over finite fields there is a natural invariant of representations that provides strong information on the character ratio. We call this invariant rank. <br />
<br />
This talk will discuss the notion of rank for the group GLn over finite fields, demonstrate how it controls the character ratio, and explain how one can apply the results to verify mixing time and rate for certain random walks.<br />
<br />
This is joint work with Roger Howe (Yale and Texas AM). The numerics for this work was carried by Steve Goldstein (Madison)<br />
<br />
<br />
===Jose Rodriguez (UW-Madison)===<br />
<br />
Abstract: Determining the closest point to a model (subset of Euclidean space) is an important problem in many applications in science,<br />
engineering, and statistics. One way to solve this problem is by minimizing the squared Euclidean distance function using a gradient<br />
descent approach. However, when there are multiple local minima, there is no guarantee of convergence to the true global minimizer.<br />
An alternative method is to determine the critical points of an objective function on the model.<br />
In algebraic statistics, the models of interest are algebraic sets, i.e., solution sets to a system of multivariate polynomial equations. In this situation, the number of critical points of the squared Euclidean distance function on the model’s Zariski closure is a topological invariant called the Euclidean distance degree (ED degree).<br />
In this talk, I will present some models from computer vision and statistics that may be described as algebraic sets. Moreover,<br />
I will describe a topological method for determining a Euclidean distance degree and a numerical algebraic geometry approach for<br />
determining critical points of the squared Euclidean distance function.<br />
<br />
<br />
===Ananth Shankar (MIT)===<br />
<br />
Abstract: An abelian surface 'splits' if it admits a non-trivial map to some elliptic curve. It is well known that the set of abelian surfaces that split are sparse in the set of all abelian surfaces. Nevertheless, we prove that there are infinitely many split abelian surfaces in arithmetic one-parameter families of generically non-split abelian surfaces. I will describe this work, and if time permits, mention generalizations of this result to the setting of K3 surfaces, as well as applications to the dynamics of hecke orbits. This is joint work with Tang, Maulik-Tang, and Shankar-Tang-Tayou.<br />
<br />
<br />
===Franca Hoffman (Caltech)===<br />
<br />
Title: Gradient Flows: From PDE to Data Analysis.<br />
<br />
Abstract: Certain diffusive PDEs can be viewed as infinite-dimensional gradient flows. This fact has led to the development of new tools in various areas of mathematics ranging from PDE theory to data science. In this talk, we focus on two different directions: model-driven approaches and data-driven approaches.<br />
In the first part of the talk we use gradient flows for analyzing non-linear and non-local aggregation-diffusion equations when the corresponding energy functionals are not necessarily convex. Moreover, the gradient flow structure enables us to make connections to well-known functional inequalities, revealing possible links between the optimizers of these inequalities and the equilibria of certain aggregation-diffusion PDEs.<br />
In the second part, we use and develop gradient flow theory to design novel tools for data analysis. We draw a connection between gradient flows and Ensemble Kalman methods for parameter estimation. We introduce the Ensemble Kalman Sampler - a derivative-free methodology for model calibration and uncertainty quantification in expensive black-box models. The interacting particle dynamics underlying our algorithm can be approximated by a novel gradient flow structure in a modified Wasserstein metric which reflects particle correlations. The geometry of this modified Wasserstein metric is of independent theoretical interest.<br />
<br />
<br />
=== Jeffrey Danciger (UT Austin) ===<br />
<br />
Title: Affine geometry and the Auslander Conjecture<br />
<br />
Abstract: The Auslander Conjecture is an analogue of Bieberbach’s theory of Euclidean crystallographic groups in the setting of affine geometry. It predicts that a complete affine manifold (a manifold equipped with a complete torsion-free flat affine connection) which is compact must have virtually solvable fundamental group. The conjecture is known up to dimension six, but is known to fail if the compactness assumption is removed, even in low dimensions. We discuss some history of this conjecture, give some basic examples, and then survey some recent advances in the study of non-compact complete affine manifolds with non-solvable fundamental group. <br />
Tools from the deformation theory of pseudo-Riemannian hyperbolic manifolds and also from higher Teichm&uuml;ller theory will enter the picture.<br />
<br />
<br />
=== Tatyana Shcherbina (Princeton) ===<br />
<br />
Title: Random matrix theory and supersymmetry techniques<br />
<br />
Abstract: Starting from the works of Erdos, Yau, Schlein with coauthors, the significant progress in understanding the universal behavior of many random graph and random matrix models were achieved. However for the random matrices with a special structure our understanding is still very limited. In this talk I am going to overview applications of another approach to the study of the local eigenvalues statistics in random matrix theory based on so-called supersymmetry techniques (SUSY). SUSY approach is based on the representation of the determinant as an integral over the Grassmann (anticommuting) variables. Combining this representation with the representation of an inverse determinant as an integral over the Gaussian complex field, SUSY allows to obtain an integral representation for the main spectral characteristics of random matrices such as limiting density, correlation functions, the resolvent's elements, etc. This method is widely (and successfully) used in the physics literature and is potentially very powerful but the rigorous control of the integral representations, which can be obtained by this method, is quite difficult, and it requires powerful analytic and statistical mechanics tools. In this talk we will discuss some recent progress in application of SUSY to the analysis of local spectral characteristics of the prominent ensemble of random band matrices, i.e. random matrices<br />
whose entries become negligible if their distance from the main diagonal exceeds a certain parameter called the band width. <br />
<br />
<br />
=== Tingran Gao (University of Chicago) ===<br />
<br />
Title: Manifold Learning on Fibre Bundles<br />
<br />
Abstract: Spectral geometry has played an important role in modern geometric data analysis, where the technique is widely known as Laplacian eigenmaps or diffusion maps. In this talk, we present a geometric framework that studies graph representations of complex datasets, where each edge of the graph is equipped with a non-scalar transformation or correspondence. This new framework models such a dataset as a fibre bundle with a connection, and interprets the collection of pairwise functional relations as defining a horizontal diffusion process on the bundle driven by its projection on the base. The eigenstates of this horizontal diffusion process encode the “consistency” among objects in the dataset, and provide a lens through which the geometry of the dataset can be revealed. We demonstrate an application of this geometric framework on evolutionary anthropology.<br />
<br />
<br />
=== Andrew Zimmer (LSU) ===<br />
<br />
Title: Intrinsic and extrinsic geometries in several complex variables<br />
<br />
Abstract: A bounded domain in complex Euclidean space, despite being one of the simplest types of manifolds, has a number of interesting geometric structures. When the domain is pseudoconvex, it has a natural intrinsic geometry: the complete Kaehler-Einstein metric constructed by Cheng-Yau and Mok-Yau. When the domain is smoothly bounded, there is also a natural extrinsic structure: the CR-geometry of the boundary. In this talk, I will describe connections between these intrinsic and extrinsic geometries. Then, I will discuss how these connections can lead to new analytic results.<br />
<br />
<br />
=== Nick Higham (Manchester) ===<br />
<br />
Title: Challenges in Multivalued Matrix Functions<br />
<br />
Abstract: In this lecture I will discuss multivalued matrix functions that arise in solving various kinds of matrix equations. The matrix logarithm is the prototypical example, and my first interaction with Hans Schneider was about this function. Another example is the Lambert W function of a matrix, which is much less well known but has been attracting recent interest. A theme of the talk is the importance of choosing appropriate principal values and making sure that the correct choices of signs and branches are used,<br />
both in theory and in computation. I will give examples where incorrect results have previously been obtained.<br />
<br />
I focus on matrix inverse trigonometric and inverse hyperbolic functions, beginning by investigating existence and characterization. Turning to the principal values, various functional identities are derived, some of which are new even in the scalar case, including a “round trip” formula that relates acos(cos A) to A and similar formulas for the other inverse functions. Key tools used in the derivations are the matrix unwinding function and the matrix sign function.<br />
<br />
A new inverse scaling and squaring type algorithm employing a Schur decomposition and variable-degree Pade approximation is derived for computing acos, and it is shown how it can also be used to compute asin, acosh, and asinh.<br />
<br />
<br />
=== Hui Yu (Columbia) ===<br />
<br />
Title: Singular sets in obstacle problems<br />
<br />
Abstract: One of the most important free boundary problems is the obstacle problem. The regularity of its free boundary has been studied for over half a century. In this talk, we review some classical results as well as exciting new developments. In particular, we discuss the recent resolution of the regularity of the singular set for the fully nonlinear obstacle problem. This talk is based on a joint work with Ovidiu Savin at Columbia University.<br />
<br />
== Future Colloquia ==<br />
[[Colloquia/Fall 2020| Fall 2020]]<br />
<br />
== Past Colloquia ==<br />
<br />
[[Colloquia/Blank|Blank]]<br />
<br />
[[Colloquia/Spring2019|Spring 2019]]<br />
<br />
[[Colloquia/Fall2018|Fall 2018]]<br />
<br />
[[Colloquia/Spring2018|Spring 2018]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=18406Applied/Physical Applied Math2019-11-13T17:36:12Z<p>Jeanluc: /* Fall 2019 */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a departmental meeting)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Sept. 5<br />
|<br />
|Organizational meeting<br />
|-<br />
|Sept. 12<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Sept. 19<br />
|Yu<br />
|Convection-induced singularity suppression in the Keller-Segel and other nonlinear PDEs<br />
|-<br />
|Sept. 26<br />
|Son<br />
|State-constraint static Hamilton-Jacobi equations in nested domains<br />
|-<br />
|Oct. 3<br />
|Hongfei<br />
|Microswimmers interacting with walls<br />
|-<br />
|Oct. 10<br />
|Alex Townsend<br />
|The ultraspherical spectral method<br />
|-<br />
|Oct. 17<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Oct. 24<br />
|Prerna<br />
||Pak, Feng and Stone, [https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/viscous-marangoni-migration-of-a-drop-in-a-poiseuille-flow-at-low-surface-peclet-numbers/2504CA0D4BC84B06E2E33DA39DE93355 Viscous Marangoni migration of a drop in a Poiseuille flow at low surface Péclet numbers].<br />
|-<br />
|Oct. 31<br />
|''no meeting''<br />
|<br />
|-<br />
|Nov. 7<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Nov. 14<br />
|Bryan<br />
|Vanneste, [https://journals.aps.org/pre/abstract/10.1103/PhysRevE.81.036701 Estimating generalized Lyapunov exponents for products of random matrices]<br />
|-<br />
|Nov. 21<br />
|<br />
|Practice talks for DFD<br />
|-<br />
|Dec. 5<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Dec. 12<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Spring2019|Spring 2019]]<br />
*[[Applied/Physical_Applied_Math/Fall2018|Fall 2018]]<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=SIAM_Student_Chapter_Seminar&diff=18318SIAM Student Chapter Seminar2019-11-04T15:43:16Z<p>Jeanluc: /* Past Semesters */</p>
<hr />
<div>__NOTOC__<br />
<br />
*'''When:''' Most Friday at 11:30am<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~xshen/ Xiao Shen]<br />
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] <br />
*'''To join the SIAM Chapter mailing list:''' email [join-siam-chapter@lists.wisc.edu].<br />
<br />
<br><br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Sept. 27, Oct. 4 <br />
|[http://www.math.wisc.edu/~xshen/ Xiao Shen] (Math)<br />
|''[[#Sep 27, Oct 4: Xiao Shen (Math)|The corner growth model]]''<br />
|-<br />
|Oct. 11<br />
|''no seminar''<br />
|<br />
|-<br />
|-<br />
|Oct. 18 <br />
|[https://scholar.google.com/citations?user=7cVl9IkAAAAJ&hl=en Bhumesh Kumar] (EE)<br />
|''[[#Oct 18: Bhumesh Kumar (EE)|Non-stationary Stochastic Approximation]]''<br />
|<br />
|-<br />
|-<br />
|Oct. 25 <br />
|Max Bacharach (Math)<br />
|''[[#Oct 25:|Coalescent with Recombination]]''<br />
|-<br />
|-<br />
|Nov. 1<br />
|''no seminar''<br />
|<br />
|-<br />
|-<br />
|Nov. 8<br />
|<br />
|<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
=== Sep 27, Oct 4: Xiao Shen (Math) ===<br />
'''The corner growth model'''<br />
<br />
Imagine there is an arbitrary amount of donuts attached to the integer points of Z^2. The goal is to pick an optimal up-right path which allows you to eat as much donuts as possible along the way. We will look at some basic combinatorial observations, and how specific probability distribution would help us to study this model.<br />
<br />
=== Oct 18: Bhumesh Kumar (EE) ===<br />
'''Non-stationary Stochastic Approximation'''<br />
<br />
Abstract: Robbins–Monro pioneered a general framework for stochastic approximation to find roots of a function with just noisy evaluations.With applications in optimization, signal processing and control theory there is resurged interest in time-varying aka non-stationary functions. This works addresses that premise by providing explicit, all time, non-asymptotic tracking error bounds via Alekseev's nonlinear variations of constant formula. <br />
<br />
Reference: https://arxiv.org/abs/1802.07759 (To appear in Mathematics of Control, Signals and Systems)<br />
<br />
=== Oct 25: Max Bacharach (Math) ===<br />
'''Coalescent with Recombination'''<br />
<br />
I will talk about the continuous time coalescent with mutation and recombination, with a focus on introducing key concepts related to genetic distance and evolutionary relatedness. The talk will be informal and accessible.<br />
<br />
<br><br />
<br />
== Past Semesters ==<br />
*[[SIAM_Student_Chapter_Seminar/Fall2018|Fall 2018]]<br />
*[[SIAM_Student_Chapter_Seminar/Spring2017|Spring 2017]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=SIAM_Student_Chapter_Seminar/Spring2017&diff=18317SIAM Student Chapter Seminar/Spring20172019-11-04T15:42:48Z<p>Jeanluc: Create page from old website.</p>
<hr />
<div>= Spring 2017<br />
<br />
Date Speaker Title<br />
<br />
March 17 Polly Yu Zeeman deceleration: motivation, simulation and experiment<br />
<br />
March 31 Alisha Zachariah Low Complexity (RADAR) Channel Estimation<br />
<br />
April 14 Jim Brunner Robust permanence of polynomial dynamical systems<br />
<br />
April 28 Zachary Charles Subspace clustering with missing data<br />
<br />
<br />
<br />
<br />
<br />
<br />
Abstracts (2017 Spring)<br />
April 28: Zachary Charles<br />
Title: Subspace clustering with missing data<br />
<br />
Abstract: In many applications (recommender systems, GPS, medical records) we want to recover a matrix given from an incomplete sampling of its entries. Up to this point, work in this area has focused on the case that the underlying matrix is low rank. Unfortunately, this low-rank assumption is often not true in real-life settings. We instead consider the case when the columns of the matrix come from a union of low rank subspaces. This type of model has already been used to great effect in computer vision and image processing. We will show that by clustering the incomplete data points in to groups according to the subspace they come from, we can often recover the true matrix efficiently. This is ongoing work with Rebecca Willett and Amin Jalali.<br />
<br />
Note from the speaker: The talk will hopefully be of interest to anybody who enjoys optimization, machine learning, high-dimensional probability, or convex analysis. However, I will not assume background in any of those areas.<br />
<br />
April 14: Jim Brunner<br />
Title: Robust permanence of polynomial dynamical systems<br />
<br />
Abstract: A ``permanent" dynamical system is one whose positive solutions stay bounded away from zero and infinity. The permanence property has important applications in biochemistry, cell biology, and ecology. Inspired by reaction network theory, we define a class of polynomial dynamical systems called {\it tropically endotactic}. We show that these polynomial dynamical systems are permanent, irrespective to the values of (possibly time-dependent) parameters in these systems. These results generalize the permanence of 2D reversible and weakly reversible mass-action systems.<br />
<br />
Comment on the abstract (from Jim): While this talk sounds like a technical analysis talk, I want to emphasize that the interesting thing for the SIAM student chapter is not so much the result but instead the method of proof. I’ll introduce a thing called a “differential inclusion” and try to convince people that we can analyze ODE systems with polynomial right hand sides by turning our heads and squinting at them in the correct way.<br />
<br />
March 31: Alisha Zachariah<br />
Title: Low Complexity (RADAR) Channel Estimation<br />
<br />
Abstract: Several forms of wireless communication involve estimating the channel through which signals are sent. In this talk we will focus on the RADAR channel. My main motivation in this talk is to present an algebraic channel model that has a sophisticated underlying structure. I will present an existing algorithm that uses this and then develop a low complexity improvement that the structure suggests.<br />
<br />
March 17: Polly Yu<br />
Title: Zeeman deceleration: motivation, simulation and experiment<br />
<br />
Abstract: Granted there will be a lot of 'I don't know's, allow me to introduce the idea of cooling a particle beam by magnetic field. Specifically, I will talk about hydrogen atoms, and how to experimentally implement this cooling. Numerical simulation results will be presented along with pretty pictures. Some experimental data (for the non-decelerated beam) will also be presented; they don't look as pretty, but they remind us that experiments are hard, so patience needed when working with experimentalists.</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=SIAM_Student_Chapter_Seminar&diff=18316SIAM Student Chapter Seminar2019-11-04T15:39:25Z<p>Jeanluc: </p>
<hr />
<div>__NOTOC__<br />
<br />
*'''When:''' Most Friday at 11:30am<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~xshen/ Xiao Shen]<br />
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] <br />
*'''To join the SIAM Chapter mailing list:''' email [join-siam-chapter@lists.wisc.edu].<br />
<br />
<br><br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Sept. 27, Oct. 4 <br />
|[http://www.math.wisc.edu/~xshen/ Xiao Shen] (Math)<br />
|''[[#Sep 27, Oct 4: Xiao Shen (Math)|The corner growth model]]''<br />
|-<br />
|Oct. 11<br />
|''no seminar''<br />
|<br />
|-<br />
|-<br />
|Oct. 18 <br />
|[https://scholar.google.com/citations?user=7cVl9IkAAAAJ&hl=en Bhumesh Kumar] (EE)<br />
|''[[#Oct 18: Bhumesh Kumar (EE)|Non-stationary Stochastic Approximation]]''<br />
|<br />
|-<br />
|-<br />
|Oct. 25 <br />
|Max Bacharach (Math)<br />
|''[[#Oct 25:|Coalescent with Recombination]]''<br />
|-<br />
|-<br />
|Nov. 1<br />
|''no seminar''<br />
|<br />
|-<br />
|-<br />
|Nov. 8<br />
|<br />
|<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
=== Sep 27, Oct 4: Xiao Shen (Math) ===<br />
'''The corner growth model'''<br />
<br />
Imagine there is an arbitrary amount of donuts attached to the integer points of Z^2. The goal is to pick an optimal up-right path which allows you to eat as much donuts as possible along the way. We will look at some basic combinatorial observations, and how specific probability distribution would help us to study this model.<br />
<br />
=== Oct 18: Bhumesh Kumar (EE) ===<br />
'''Non-stationary Stochastic Approximation'''<br />
<br />
Abstract: Robbins–Monro pioneered a general framework for stochastic approximation to find roots of a function with just noisy evaluations.With applications in optimization, signal processing and control theory there is resurged interest in time-varying aka non-stationary functions. This works addresses that premise by providing explicit, all time, non-asymptotic tracking error bounds via Alekseev's nonlinear variations of constant formula. <br />
<br />
Reference: https://arxiv.org/abs/1802.07759 (To appear in Mathematics of Control, Signals and Systems)<br />
<br />
=== Oct 25: Max Bacharach (Math) ===<br />
'''Coalescent with Recombination'''<br />
<br />
I will talk about the continuous time coalescent with mutation and recombination, with a focus on introducing key concepts related to genetic distance and evolutionary relatedness. The talk will be informal and accessible.<br />
<br />
<br><br />
<br />
== Past Semesters ==<br />
*[[SIAM_Student_Chapter_Seminar/Fall2018|Fall 2018]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=SIAM_Student_Chapter_Seminar/Fall2018&diff=18315SIAM Student Chapter Seminar/Fall20182019-11-04T15:38:11Z<p>Jeanluc: Created page with "__NOTOC__ == Fall 2018 == {| cellpadding="8" !align="left" | date !align="left" | speaker !align="left" | title |- | Sept. 12 |[http://www.math.wisc.edu/~ke/ Ke Chen] (Math..."</p>
<hr />
<div>__NOTOC__<br />
<br />
== Fall 2018 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
| Sept. 12<br />
|[http://www.math.wisc.edu/~ke/ Ke Chen] (Math)<br />
|''[[#Sep 12: Ke Chen (Math)|Inverse Problem in Optical Tomography]]''<br />
|-<br />
| Spet. 26 <br />
|[http://www.math.wisc.edu/~kehlert/ Kurt Ehlert] (Math)<br />
|''[[#Sept 26: Kurt Ehlert (Math)| How to bet when gambling]]''<br />
|-<br />
| Oct. 10 <br />
|[http://TBD Zachary Hansen] (Atmospheric and Oceanic Sciences)<br />
|''[[#Oct 10: Zachary Hansen (Atmospheric and Oceanic Sciences)| Land-Ocean contrast in lightning ]]''<br />
|-<br />
| Oct. 24 <br />
|[http://TBD Xuezhou Zhang] (Computer Science)<br />
|''[[#Oct 24: Xuezhou Zhang (Computer Science)| An Optimal Control Approach to Sequential Machine Teaching ]]''<br />
|-<br />
| Nov. 7 <br />
|[http://TBD Cancelled] <br />
|''[[#Nov 7: Cancelled| ]]''<br />
|-<br />
| Nov. 21 <br />
|[http://TBD Cancelled due to Thanksgiving] <br />
|''[[#Nov 21: Cancelled| ]]''<br />
|-<br />
| Nov. 28 <br />
|[http://TBD Xiaowu Dai] (Statistics) <br />
|''[[#Nov 28: Xiaowu Dai (Statistics)| Toward the Theoretical Understanding of Large-batch Training in Stochastic Gradient Descent ]]''<br />
|-<br />
|<br />
|}<br />
<br />
<br />
== Abstract ==<br />
<br />
=== Sep 12: Ke Chen (Math) ===<br />
Inverse Problem in Optical Tomography<br />
<br />
I will briefly talk about my researches on the inverse problems of radiative transfer equations, which is usually used as a model to describe the transport of neutrons or other particles in a certain media. Such inverse problems considers the following question: given the knowledge of multiple data collected at the boundary of the domain of interest, is it possible to reconstruct the optical property of the interior of media? In this talk, I will show you that stability of this problem is deteriorating as the Knudsen number is getter smaller. The talk will be introductory and anyone graduate is welcome to join us.<br />
<br />
=== Sept 26: Kurt Ehlert (Math) ===<br />
How to bet when gambling<br />
<br />
When gambling, typically casinos have an edge. But sometimes we can gain an edge by counting cards or other means. And sometimes we have an edge in the biggest casino of all: the financial markets. When we do have an advantage, then we still need to decide how much to bet. Bet too little, and we leave money on the table. Bet too much, and we risk financial ruin. We will discuss the "Kelly criterion", which is a betting strategy that is optimal in many senses.<br />
<br />
=== Oct 10: Zachary Hansen (Atmospheric and Oceanic Sciences) ===<br />
Land-Ocean contrast in lightning<br />
<br />
Land surfaces have orders of magnitude more lightning flashes than ocean surfaces. One explanation for this difference is that land surfaces may generate greater convective available potential energy (CAPE), which fuels stronger thunderstorms. Using a high resolution cloud-resolving atmospheric model, we test whether an island can produce stronger thunderstorms just by having a land-like surface. We find that the island alters the distribution of rainfall but does not produce stronger storms. An equilibrium state known as boundary layer quasi-equilibrium follows, and is explored in more detail.<br />
<br />
=== Oct 24: Xuezhou Zhang (Computer Science) ===<br />
An Optimal Control Approach to Sequential Machine Teaching<br />
<br />
Given a sequential learning algorithm and a target model, sequential machine teaching aims to find the shortest training sequence to drive the learning algorithm to the target model. We present the first principled way to find such shortest training sequences. Our key insight is to formulate sequential machine teaching as a time-optimal control problem. This allows us to solve sequential teaching by leveraging key theoretical and computational tools developed over the past 60 years in the optimal control community. Specifically, we study the Pontryagin Maximum Principle, which yields a necessary condition for opti- mality of a training sequence. We present analytic, structural, and numerical implica- tions of this approach on a case study with a least-squares loss function and gradient de- scent learner. We compute optimal train- ing sequences for this problem, and although the sequences seem circuitous, we find that they can vastly outperform the best available heuristics for generating training sequences.<br />
<br />
=== Nov 7: Cancelled ===<br />
<br />
=== Nov 21: Cancelled ===<br />
<br />
=== Nov 28: Xiaowu Dai (Statistics) ===<br />
Toward the Theoretical Understanding of Large-batch Training in Stochastic Gradient Descent<br />
<br />
Stochastic gradient descent (SGD) is almost ubiquitously used for training nonconvex optimization tasks including deep neural networks. Recently, a hypothesis that "large batch SGD tends to converge to sharp minimizers of training function" has received increasing attention. We develop some new theory to give a justification of this hypothesis. In particular, we provide new properties of SGD in both finite-time and asymptotic regimes, with the tools from empirical processes and Partial Differential Equations. A connection between the stochasticity in SGD and the idea of smoothing splines in nonparametric statistics is also built. We include numerical experiments to corroborate these theoretical findings.</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=SIAM_Student_Chapter_Seminar&diff=18314SIAM Student Chapter Seminar2019-11-04T15:34:41Z<p>Jeanluc: /* Abstract */</p>
<hr />
<div>__NOTOC__<br />
<br />
*'''When:''' Most Friday at 11:30am<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~xshen/ Xiao Shen]<br />
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] <br />
*'''To join the SIAM Chapter mailing list:''' email [join-siam-chapter@lists.wisc.edu].<br />
<br />
<br><br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Sept. 27, Oct. 4 <br />
|[http://www.math.wisc.edu/~xshen/ Xiao Shen] (Math)<br />
|''[[#Sep 27, Oct 4: Xiao Shen (Math)|The corner growth model]]''<br />
|-<br />
|Oct. 11<br />
|''no seminar''<br />
|<br />
|-<br />
|-<br />
|Oct. 18 <br />
|[https://scholar.google.com/citations?user=7cVl9IkAAAAJ&hl=en Bhumesh Kumar] (EE)<br />
|''[[#Oct 18: Bhumesh Kumar (EE)|Non-stationary Stochastic Approximation]]''<br />
|<br />
|-<br />
|-<br />
|Oct. 25 <br />
|Max Bacharach (Math)<br />
|''[[#Oct 25:|Coalescent with Recombination]]''<br />
|-<br />
|-<br />
|Nov. 1<br />
|''no seminar''<br />
|<br />
|-<br />
|-<br />
|Nov. 8<br />
|<br />
|<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
=== Sep 27, Oct 4: Xiao Shen (Math) ===<br />
'''The corner growth model'''<br />
<br />
Imagine there is an arbitrary amount of donuts attached to the integer points of Z^2. The goal is to pick an optimal up-right path which allows you to eat as much donuts as possible along the way. We will look at some basic combinatorial observations, and how specific probability distribution would help us to study this model.<br />
<br />
=== Oct 18: Bhumesh Kumar (EE) ===<br />
'''Non-stationary Stochastic Approximation'''<br />
<br />
Abstract: Robbins–Monro pioneered a general framework for stochastic approximation to find roots of a function with just noisy evaluations.With applications in optimization, signal processing and control theory there is resurged interest in time-varying aka non-stationary functions. This works addresses that premise by providing explicit, all time, non-asymptotic tracking error bounds via Alekseev's nonlinear variations of constant formula. <br />
<br />
Reference: https://arxiv.org/abs/1802.07759 (To appear in Mathematics of Control, Signals and Systems)<br />
<br />
=== Oct 25: Max Bacharach (Math) ===<br />
'''Coalescent with Recombination'''<br />
<br />
I will talk about the continuous time coalescent with mutation and recombination, with a focus on introducing key concepts related to genetic distance and evolutionary relatedness. The talk will be informal and accessible.<br />
<br />
<br></div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=SIAM_Student_Chapter_Seminar&diff=18313SIAM Student Chapter Seminar2019-11-04T15:33:35Z<p>Jeanluc: /* Fall 2019 */</p>
<hr />
<div>__NOTOC__<br />
<br />
*'''When:''' Most Friday at 11:30am<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~xshen/ Xiao Shen]<br />
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] <br />
*'''To join the SIAM Chapter mailing list:''' email [join-siam-chapter@lists.wisc.edu].<br />
<br />
<br><br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Sept. 27, Oct. 4 <br />
|[http://www.math.wisc.edu/~xshen/ Xiao Shen] (Math)<br />
|''[[#Sep 27, Oct 4: Xiao Shen (Math)|The corner growth model]]''<br />
|-<br />
|Oct. 11<br />
|''no seminar''<br />
|<br />
|-<br />
|-<br />
|Oct. 18 <br />
|[https://scholar.google.com/citations?user=7cVl9IkAAAAJ&hl=en Bhumesh Kumar] (EE)<br />
|''[[#Oct 18: Bhumesh Kumar (EE)|Non-stationary Stochastic Approximation]]''<br />
|<br />
|-<br />
|-<br />
|Oct. 25 <br />
|Max Bacharach (Math)<br />
|''[[#Oct 25:|Coalescent with Recombination]]''<br />
|-<br />
|-<br />
|Nov. 1<br />
|''no seminar''<br />
|<br />
|-<br />
|-<br />
|Nov. 8<br />
|<br />
|<br />
|}<br />
<br />
== Abstract ==<br />
<br />
=== Sep 27, Oct 4: Xiao Shen (Math) ===<br />
'''The corner growth model'''<br />
<br />
Imagine there is an arbitrary amount of donuts attached to the integer points of Z^2. The goal is to pick an optimal up-right path which allows you to eat as much donuts as possible along the way. We will look at some basic combinatorial observations, and how specific probability distribution would help us to study this model.<br />
<br />
=== Oct 18: Bhumesh Kumar (EE) ===<br />
'''Non-stationary Stochastic Approximation'''<br />
<br />
Abstract: Robbins–Monro pioneered a general framework for stochastic approximation to find roots of a function with just noisy evaluations.With applications in optimization, signal processing and control theory there is resurged interest in time-varying aka non-stationary functions. This works addresses that premise by providing explicit, all time, non-asymptotic tracking error bounds via Alekseev's nonlinear variations of constant formula. <br />
<br />
Reference: https://arxiv.org/abs/1802.07759 (To appear in Mathematics of Control, Signals and Systems)<br />
<br />
=== Oct 25: Max Bacharach (Math) ===<br />
'''Coalescent with Recombination'''<br />
<br />
I will talk about the continuous time coalescent with mutation and recombination, with a focus on introducing key concepts related to genetic distance and evolutionary relatedness. The talk will be informal and accessible.<br />
<br />
<br></div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=SIAM_Student_Chapter_Seminar&diff=18312SIAM Student Chapter Seminar2019-11-04T15:32:31Z<p>Jeanluc: </p>
<hr />
<div>__NOTOC__<br />
<br />
*'''When:''' Most Friday at 11:30am<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~xshen/ Xiao Shen]<br />
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] <br />
*'''To join the SIAM Chapter mailing list:''' email [join-siam-chapter@lists.wisc.edu].<br />
<br />
<br><br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Sept. 27, Oct. 4 <br />
|[http://www.math.wisc.edu/~xshen/ Xiao Shen] (Math)<br />
|''[[#Sep 27, Oct 4: Xiao Shen (Math)|The corner growth model]]''<br />
|-<br />
|Oct. 11<br />
|''no seminar''<br />
|<br />
|-<br />
|-<br />
|Oct. 18 <br />
|[https://scholar.google.com/citations?user=7cVl9IkAAAAJ&hl=en Bhumesh Kumar] (EE)<br />
|''[[#Oct 18: Bhumesh Kumar (EE)|Non-stationary Stochastic Approximation]]''<br />
|<br />
|-<br />
|-<br />
|Oct. 25 <br />
|Max Bacharach<br />
|''[[#Oct 25:|Coalescent with Recombination]]''<br />
|-<br />
|-<br />
|Nov. 1<br />
|''no seminar''<br />
|<br />
|-<br />
|-<br />
|Nov. 8<br />
|<br />
|<br />
|}<br />
<br />
== Abstract ==<br />
<br />
=== Sep 27, Oct 4: Xiao Shen (Math) ===<br />
'''The corner growth model'''<br />
<br />
Imagine there is an arbitrary amount of donuts attached to the integer points of Z^2. The goal is to pick an optimal up-right path which allows you to eat as much donuts as possible along the way. We will look at some basic combinatorial observations, and how specific probability distribution would help us to study this model.<br />
<br />
=== Oct 18: Bhumesh Kumar (EE) ===<br />
'''Non-stationary Stochastic Approximation'''<br />
<br />
Abstract: Robbins–Monro pioneered a general framework for stochastic approximation to find roots of a function with just noisy evaluations.With applications in optimization, signal processing and control theory there is resurged interest in time-varying aka non-stationary functions. This works addresses that premise by providing explicit, all time, non-asymptotic tracking error bounds via Alekseev's nonlinear variations of constant formula. <br />
<br />
Reference: https://arxiv.org/abs/1802.07759 (To appear in Mathematics of Control, Signals and Systems)<br />
<br />
=== Oct 25: Max Bacharach (Math) ===<br />
'''Coalescent with Recombination'''<br />
<br />
I will talk about the continuous time coalescent with mutation and recombination, with a focus on introducing key concepts related to genetic distance and evolutionary relatedness. The talk will be informal and accessible.<br />
<br />
<br></div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=SIAM_Student_Chapter_Seminar&diff=18311SIAM Student Chapter Seminar2019-11-04T15:30:06Z<p>Jeanluc: /* Abstract */</p>
<hr />
<div>__NOTOC__<br />
<br />
<br />
<br />
*'''When:''' Most Friday at 11:30 am (see e-mail)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~xshen/ Xiao Shen] <br />
*'''To join the SIAM Chapter mailing list:''' email [join-siam-chapter@lists.wisc.edu].<br />
<br />
<br><br />
<br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Sept. 27, Oct. 4 <br />
|[http://www.math.wisc.edu/~xshen/ Xiao Shen] (Math)<br />
|''[[#Sep 27, Oct 4: Xiao Shen (Math)|The corner growth model]]''<br />
|-<br />
|Oct. 11<br />
|''no seminar''<br />
|<br />
|-<br />
|-<br />
|Oct. 18 <br />
|[https://scholar.google.com/citations?user=7cVl9IkAAAAJ&hl=en Bhumesh Kumar] (EE)<br />
|''[[#Oct 18: Bhumesh Kumar (EE)|Non-stationary Stochastic Approximation]]''<br />
|<br />
|-<br />
|-<br />
|Oct. 25 <br />
|Max Bacharach<br />
|''[[#Oct 25:|Coalescent with Recombination]]''<br />
|-<br />
|-<br />
|Nov. 1<br />
|''no seminar''<br />
|<br />
|-<br />
|-<br />
|Nov. 8<br />
|<br />
|<br />
|}<br />
<br />
== Abstract ==<br />
<br />
=== Sep 27, Oct 4: Xiao Shen (Math) ===<br />
'''The corner growth model'''<br />
<br />
Imagine there is an arbitrary amount of donuts attached to the integer points of Z^2. The goal is to pick an optimal up-right path which allows you to eat as much donuts as possible along the way. We will look at some basic combinatorial observations, and how specific probability distribution would help us to study this model.<br />
<br />
=== Oct 18: Bhumesh Kumar (EE) ===<br />
'''Non-stationary Stochastic Approximation'''<br />
<br />
Abstract: Robbins–Monro pioneered a general framework for stochastic approximation to find roots of a function with just noisy evaluations.With applications in optimization, signal processing and control theory there is resurged interest in time-varying aka non-stationary functions. This works addresses that premise by providing explicit, all time, non-asymptotic tracking error bounds via Alekseev's nonlinear variations of constant formula. <br />
<br />
Reference: https://arxiv.org/abs/1802.07759 (To appear in Mathematics of Control, Signals and Systems)<br />
<br />
=== Oct 25: Max Bacharach (Math) ===<br />
'''Coalescent with Recombination'''<br />
<br />
I will talk about the continuous time coalescent with mutation and recombination, with a focus on introducing key concepts related to genetic distance and evolutionary relatedness. The talk will be informal and accessible.<br />
<br />
<br></div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=SIAM_Student_Chapter_Seminar&diff=18310SIAM Student Chapter Seminar2019-11-04T15:29:56Z<p>Jeanluc: /* Abstract */</p>
<hr />
<div>__NOTOC__<br />
<br />
<br />
<br />
*'''When:''' Most Friday at 11:30 am (see e-mail)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~xshen/ Xiao Shen] <br />
*'''To join the SIAM Chapter mailing list:''' email [join-siam-chapter@lists.wisc.edu].<br />
<br />
<br><br />
<br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Sept. 27, Oct. 4 <br />
|[http://www.math.wisc.edu/~xshen/ Xiao Shen] (Math)<br />
|''[[#Sep 27, Oct 4: Xiao Shen (Math)|The corner growth model]]''<br />
|-<br />
|Oct. 11<br />
|''no seminar''<br />
|<br />
|-<br />
|-<br />
|Oct. 18 <br />
|[https://scholar.google.com/citations?user=7cVl9IkAAAAJ&hl=en Bhumesh Kumar] (EE)<br />
|''[[#Oct 18: Bhumesh Kumar (EE)|Non-stationary Stochastic Approximation]]''<br />
|<br />
|-<br />
|-<br />
|Oct. 25 <br />
|Max Bacharach<br />
|''[[#Oct 25:|Coalescent with Recombination]]''<br />
|-<br />
|-<br />
|Nov. 1<br />
|''no seminar''<br />
|<br />
|-<br />
|-<br />
|Nov. 8<br />
|<br />
|<br />
|}<br />
<br />
== Abstract ==<br />
<br />
=== Sep 27, Oct 4: Xiao Shen (Math) ===<br />
'''The corner growth model'''<br />
<br />
Imagine there is an arbitrary amount of donuts attached to the integer points of Z^2. The goal is to pick an optimal up-right path which allows you to eat as much donuts as possible along the way. We will look at some basic combinatorial observations, and how specific probability distribution would help us to study this model.<br />
<br />
<br />
=== Oct 18: Bhumesh Kumar (EE) ===<br />
'''Non-stationary Stochastic Approximation'''<br />
<br />
Abstract: Robbins–Monro pioneered a general framework for stochastic approximation to find roots of a function with just noisy evaluations.With applications in optimization, signal processing and control theory there is resurged interest in time-varying aka non-stationary functions. This works addresses that premise by providing explicit, all time, non-asymptotic tracking error bounds via Alekseev's nonlinear variations of constant formula. <br />
<br />
Reference: https://arxiv.org/abs/1802.07759 (To appear in Mathematics of Control, Signals and Systems)<br />
<br />
=== Oct 25: Max Bacharach (Math) ===<br />
'''Coalescent with Recombination'''<br />
<br />
I will talk about the continuous time coalescent with mutation and recombination, with a focus on introducing key concepts related to genetic distance and evolutionary relatedness. The talk will be informal and accessible.<br />
<br />
<br></div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=SIAM_Student_Chapter_Seminar&diff=18309SIAM Student Chapter Seminar2019-11-04T15:29:14Z<p>Jeanluc: /* Fall 2019 */</p>
<hr />
<div>__NOTOC__<br />
<br />
<br />
<br />
*'''When:''' Most Friday at 11:30 am (see e-mail)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~xshen/ Xiao Shen] <br />
*'''To join the SIAM Chapter mailing list:''' email [join-siam-chapter@lists.wisc.edu].<br />
<br />
<br><br />
<br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Sept. 27, Oct. 4 <br />
|[http://www.math.wisc.edu/~xshen/ Xiao Shen] (Math)<br />
|''[[#Sep 27, Oct 4: Xiao Shen (Math)|The corner growth model]]''<br />
|-<br />
|Oct. 11<br />
|''no seminar''<br />
|<br />
|-<br />
|-<br />
|Oct. 18 <br />
|[https://scholar.google.com/citations?user=7cVl9IkAAAAJ&hl=en Bhumesh Kumar] (EE)<br />
|''[[#Oct 18: Bhumesh Kumar (EE)|Non-stationary Stochastic Approximation]]''<br />
|<br />
|-<br />
|-<br />
|Oct. 25 <br />
|Max Bacharach<br />
|''[[#Oct 25:|Coalescent with Recombination]]''<br />
|-<br />
|-<br />
|Nov. 1<br />
|''no seminar''<br />
|<br />
|-<br />
|-<br />
|Nov. 8<br />
|<br />
|<br />
|}<br />
<br />
== Abstract ==<br />
<br />
=== Sep 27, Oct 4: Xiao Shen (Math) ===<br />
'''The corner growth model'''<br />
<br />
Imagine there is an arbitrary amount of donuts attached to the integer points of Z^2. The goal is to pick an optimal up-right path which allows you to eat as much donuts as possible along the way. We will look at some basic combinatorial observations, and how specific probability distribution would help us to study this model.<br />
<br />
<br />
=== Oct 18: Bhumesh Kumar (EE) ===<br />
'''Non-stationary Stochastic Approximation'''<br />
<br />
Abstract: Robbins–Monro pioneered a general framework for stochastic approximation to find roots of a function with just noisy evaluations.With applications in optimization, signal processing and control theory there is resurged interest in time-varying aka non-stationary functions. This works addresses that premise by providing explicit, all time, non-asymptotic tracking error bounds via Alekseev's nonlinear variations of constant formula. <br />
<br />
Reference: https://arxiv.org/abs/1802.07759 (To appear in Mathematics of Control, Signals and Systems)<br />
<br />
=== Oct 25 ===<br />
'''Coalescent with Recombination'''<br />
<br />
I will talk about the continuous time coalescent with mutation and recombination, with a focus on introducing key concepts related to genetic distance and evolutionary relatedness. The talk will be informal and accessible.<br />
<br />
<br></div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=18301Applied/Physical Applied Math2019-11-04T12:25:35Z<p>Jeanluc: /* Fall 2019 */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a departmental meeting)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Sept. 5<br />
|<br />
|Organizational meeting<br />
|-<br />
|Sept. 12<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Sept. 19<br />
|Yu<br />
|Convection-induced singularity suppression in the Keller-Segel and other nonlinear PDEs<br />
|-<br />
|Sept. 26<br />
|Son<br />
|State-constraint static Hamilton-Jacobi equations in nested domains<br />
|-<br />
|Oct. 3<br />
|Hongfei<br />
|Microswimmers interacting with walls<br />
|-<br />
|Oct. 10<br />
|Alex Townsend<br />
|The ultraspherical spectral method<br />
|-<br />
|Oct. 17<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Oct. 24<br />
|Prerna<br />
||Pak, Feng and Stone, [https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/viscous-marangoni-migration-of-a-drop-in-a-poiseuille-flow-at-low-surface-peclet-numbers/2504CA0D4BC84B06E2E33DA39DE93355 Viscous Marangoni migration of a drop in a Poiseuille flow at low surface Péclet numbers].<br />
|-<br />
|Oct. 31<br />
|''no meeting''<br />
|<br />
|-<br />
|Nov. 7<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Nov. 14<br />
|Bryan<br />
|<br />
|-<br />
|Nov. 21<br />
|<br />
|Practice talks for DFD<br />
|-<br />
|Dec. 5<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Dec. 12<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Spring2019|Spring 2019]]<br />
*[[Applied/Physical_Applied_Math/Fall2018|Fall 2018]]<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=18275Applied/Physical Applied Math2019-10-29T08:58:13Z<p>Jeanluc: Archive Fall 2018 and Spring 2019</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a departmental meeting)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Sept. 5<br />
|<br />
|Organizational meeting<br />
|-<br />
|Sept. 12<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Sept. 19<br />
|Yu<br />
|Convection-induced singularity suppression in the Keller-Segel and other nonlinear PDEs<br />
|-<br />
|Sept. 26<br />
|Son<br />
|State-constraint static Hamilton-Jacobi equations in nested domains<br />
|-<br />
|Oct. 3<br />
|Hongfei<br />
|Microswimmers interacting with walls<br />
|-<br />
|Oct. 10<br />
|Alex Townsend<br />
|The ultraspherical spectral method<br />
|-<br />
|Oct. 17<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Oct. 24<br />
|Prerna<br />
||Pak, Feng and Stone, [https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/viscous-marangoni-migration-of-a-drop-in-a-poiseuille-flow-at-low-surface-peclet-numbers/2504CA0D4BC84B06E2E33DA39DE93355 Viscous Marangoni migration of a drop in a Poiseuille flow at low surface Péclet numbers].<br />
|-<br />
|Oct. 31<br />
|''no meeting''<br />
|<br />
|-<br />
|Nov. 7<br />
|Bryan<br />
|<br />
|-<br />
|Nov. 11<br />
|<br />
|<br />
|-<br />
|Nov. 14<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Nov. 21<br />
|<br />
|Practice talks for DFD<br />
|-<br />
|Dec. 5<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Dec. 12<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|}<br />
<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Spring2019|Spring 2019]]<br />
*[[Applied/Physical_Applied_Math/Fall2018|Fall 2018]]<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math/Spring2019&diff=18274Applied/Physical Applied Math/Spring20192019-10-29T08:57:43Z<p>Jeanluc: Created page with "== Spring 2019 == {| cellpadding="8" !align="left" | date !align="left" | speaker !align="left" | title |- |Jan. 24 | |''Faculty Meeting'' |- |Jan. 31 |Jean-Luc |Organizati..."</p>
<hr />
<div>== Spring 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 24<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Jan. 31<br />
|Jean-Luc<br />
|Organizational meeting; J-LT speaks on Vortices in a channel<br />
|-<br />
|Feb. 7<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 14<br />
|Yu<br />
|Suppression of phase separation by mixing<br />
|-<br />
|Feb. 21<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 28<br />
|Bryan<br />
|Riffles shuffles and mixing<br />
|-<br />
|Mar. 7<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Mar. 14<br />
|Hongfei<br />
|[https://www.springer.com/us/book/9781441916044 Diffusion across potential barriers]<br />
|-<br />
|Mar. 21<br />
|<br />
|''Spring Break''<br />
|-<br />
|Mar. 28<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 4<br />
|Ruojun<br />
|Internal diffusion-limited aggregation and rotor-router walks with drift<br />
|-<br />
|Apr. 11<br />
|Jiajia<br />
|[https://doi.org/10.1063/1.1675038 Freed, Wiener Integrals and Models of Stiff Polymer Chains]<br />
|-<br />
|Apr. 18<br />
|Wangping<br />
|Entanglement of frictionless strings<br />
|-<br />
|Apr. 25<br />
|John<br />
|pseudo-Anosov homeomorphisms with large entropy<br />
|-<br />
|May 2<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|May 9<br />
|Saverio<br />
|Internal capillary origami (see [https://journals.aps.org/pra/abstract/10.1103/PhysRevA.44.1182 Seifert et al, Shape transformations of vesicles] and [https://www.annualreviews.org/doi/full/10.1146/annurev-fluid-122316-050130?casa_token=lYj2Hmpn0fEAAAAA:269tjv-n7Odyzgam7PniTi5WmNPjP0qVrO7qxV0a8Ox_Tl4fNsawlxTves-ev7vI_h9Sx_0jKfwK Bico et al., Elastocapillarity (Review article)])<br />
|-<br />
|}</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math/Fall2018&diff=18273Applied/Physical Applied Math/Fall20182019-10-29T08:56:53Z<p>Jeanluc: Created page with "== Fall 2018 == {| cellpadding="8" !align="left" | date !align="left" | speaker !align="left" | title |- |Jan. 31 |Jean-Luc |Organizational meeting; J-LT speaks on Aldous a..."</p>
<hr />
<div>== Fall 2018 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 31<br />
|Jean-Luc<br />
|Organizational meeting; J-LT speaks on Aldous and Diaconis, [https://www.ams.org/journals/bull/1999-36-04/S0273-0979-99-00796-X/ Longest increasing subsequences: from patience sorting to the Baik-Deift-Johansson theorem]<br />
|-<br />
|Sep. 13<br />
|Son<br />
|[https://arxiv.org/abs/1808.06129 Rate of convergence for periodic homogenization of convex Hamilton-Jacobi equations in one dimension]<br />
|-<br />
|Sep. 20<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Sep. 27<br />
|[https://www.math.cmu.edu/~gautam/sj/index.html Gautam Iyer] (CMU)<br />
|[https://arxiv.org/abs/1806.03699 Dissipation enhancement by mixing]<br />
|-<br />
|Oct. 4<br />
|Gage<br />
|[https://www.dropbox.com/s/tjc4v03cwgzeppm/Group_talk_ab___notes.pdf Escape rates of random walks on free groups]<br />
|-<br />
|Oct. 11<br />
|<i>cancelled</i><br />
|<br />
|-<br />
|Oct. 18<br />
|Yu Feng<br />
|Relaxation enhancement for Advective Cahn-Hilliard (practice for specialty)<br />
|-<br />
|Oct. 25<br />
|Yu's specialty <b>2-3pm, B139</b><br />
|Relaxation enhancement for Advective Cahn-Hilliard<br />
|-<br />
|Nov. 1<br />
|Wil<br />
|Powers, [https://journals.aps.org/rmp/abstract/10.1103/RevModPhys.82.1607; Dynamics of filaments and membranes in a viscous fluid]; Guven et al. [http://iopscience.iop.org/article/10.1088/1751-8113/47/35/355201/pdf Environmental bias and elastic curves on surfaces]<br />
|-<br />
|Nov. 8<br />
|Tom<br />
|[https://arxiv.org/abs/1809.01190 Mixing by jellyfish]<br />
|-<br />
|Nov. 15<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Nov. 22<br />
|<br />
|''Thanksgiving Break''<br />
|-<br />
|Nov. 29<br />
|Chris<br />
|Sun et al., [https://www.sciencedirect.com/science/article/pii/S0167278911001588 A mathematical model for the synchronization of cows]<br />
|-<br />
|Dec. 6<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|'''Dec. 12, B239'''<br />
|Jean-Luc<br />
|Cooking food by flipping<br />
|-<br />
|Dec. 13<br />
|<br />
|''Faculty Meeting''<br />
|}</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=18272Applied/Physical Applied Math2019-10-29T08:56:08Z<p>Jeanluc: /* Archived semesters */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a departmental meeting)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Sept. 5<br />
|<br />
|Organizational meeting<br />
|-<br />
|Sept. 12<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Sept. 19<br />
|Yu<br />
|Convection-induced singularity suppression in the Keller-Segel and other nonlinear PDEs<br />
|-<br />
|Sept. 26<br />
|Son<br />
|State-constraint static Hamilton-Jacobi equations in nested domains<br />
|-<br />
|Oct. 3<br />
|Hongfei<br />
|Microswimmers interacting with walls<br />
|-<br />
|Oct. 10<br />
|Alex Townsend<br />
|The ultraspherical spectral method<br />
|-<br />
|Oct. 17<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Oct. 24<br />
|Prerna<br />
||Pak, Feng and Stone, [https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/viscous-marangoni-migration-of-a-drop-in-a-poiseuille-flow-at-low-surface-peclet-numbers/2504CA0D4BC84B06E2E33DA39DE93355 Viscous Marangoni migration of a drop in a Poiseuille flow at low surface Péclet numbers].<br />
|-<br />
|Oct. 31<br />
|''no meeting''<br />
|<br />
|-<br />
|Nov. 7<br />
|Bryan<br />
|<br />
|-<br />
|Nov. 11<br />
|<br />
|<br />
|-<br />
|Nov. 14<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Nov. 21<br />
|<br />
|Practice talks for DFD<br />
|-<br />
|Dec. 5<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Dec. 12<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|}<br />
<br />
== Spring 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 24<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Jan. 31<br />
|Jean-Luc<br />
|Organizational meeting; J-LT speaks on Vortices in a channel<br />
|-<br />
|Feb. 7<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 14<br />
|Yu<br />
|Suppression of phase separation by mixing<br />
|-<br />
|Feb. 21<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 28<br />
|Bryan<br />
|Riffles shuffles and mixing<br />
|-<br />
|Mar. 7<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Mar. 14<br />
|Hongfei<br />
|[https://www.springer.com/us/book/9781441916044 Diffusion across potential barriers]<br />
|-<br />
|Mar. 21<br />
|<br />
|''Spring Break''<br />
|-<br />
|Mar. 28<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 4<br />
|Ruojun<br />
|Internal diffusion-limited aggregation and rotor-router walks with drift<br />
|-<br />
|Apr. 11<br />
|Jiajia<br />
|[https://doi.org/10.1063/1.1675038 Freed, Wiener Integrals and Models of Stiff Polymer Chains]<br />
|-<br />
|Apr. 18<br />
|Wangping<br />
|Entanglement of frictionless strings<br />
|-<br />
|Apr. 25<br />
|John<br />
|pseudo-Anosov homeomorphisms with large entropy<br />
|-<br />
|May 2<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|May 9<br />
|Saverio<br />
|Internal capillary origami (see [https://journals.aps.org/pra/abstract/10.1103/PhysRevA.44.1182 Seifert et al, Shape transformations of vesicles] and [https://www.annualreviews.org/doi/full/10.1146/annurev-fluid-122316-050130?casa_token=lYj2Hmpn0fEAAAAA:269tjv-n7Odyzgam7PniTi5WmNPjP0qVrO7qxV0a8Ox_Tl4fNsawlxTves-ev7vI_h9Sx_0jKfwK Bico et al., Elastocapillarity (Review article)])<br />
|-<br />
|}<br />
<br />
== Fall 2018 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 31<br />
|Jean-Luc<br />
|Organizational meeting; J-LT speaks on Aldous and Diaconis, [https://www.ams.org/journals/bull/1999-36-04/S0273-0979-99-00796-X/ Longest increasing subsequences: from patience sorting to the Baik-Deift-Johansson theorem]<br />
|-<br />
|Sep. 13<br />
|Son<br />
|[https://arxiv.org/abs/1808.06129 Rate of convergence for periodic homogenization of convex Hamilton-Jacobi equations in one dimension]<br />
|-<br />
|Sep. 20<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Sep. 27<br />
|[https://www.math.cmu.edu/~gautam/sj/index.html Gautam Iyer] (CMU)<br />
|[https://arxiv.org/abs/1806.03699 Dissipation enhancement by mixing]<br />
|-<br />
|Oct. 4<br />
|Gage<br />
|[https://www.dropbox.com/s/tjc4v03cwgzeppm/Group_talk_ab___notes.pdf Escape rates of random walks on free groups]<br />
|-<br />
|Oct. 11<br />
|<i>cancelled</i><br />
|<br />
|-<br />
|Oct. 18<br />
|Yu Feng<br />
|Relaxation enhancement for Advective Cahn-Hilliard (practice for specialty)<br />
|-<br />
|Oct. 25<br />
|Yu's specialty <b>2-3pm, B139</b><br />
|Relaxation enhancement for Advective Cahn-Hilliard<br />
|-<br />
|Nov. 1<br />
|Wil<br />
|Powers, [https://journals.aps.org/rmp/abstract/10.1103/RevModPhys.82.1607; Dynamics of filaments and membranes in a viscous fluid]; Guven et al. [http://iopscience.iop.org/article/10.1088/1751-8113/47/35/355201/pdf Environmental bias and elastic curves on surfaces]<br />
|-<br />
|Nov. 8<br />
|Tom<br />
|[https://arxiv.org/abs/1809.01190 Mixing by jellyfish]<br />
|-<br />
|Nov. 15<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Nov. 22<br />
|<br />
|''Thanksgiving Break''<br />
|-<br />
|Nov. 29<br />
|Chris<br />
|Sun et al., [https://www.sciencedirect.com/science/article/pii/S0167278911001588 A mathematical model for the synchronization of cows]<br />
|-<br />
|Dec. 6<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|'''Dec. 12, B239'''<br />
|Jean-Luc<br />
|Cooking food by flipping<br />
|-<br />
|Dec. 13<br />
|<br />
|''Faculty Meeting''<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Spring2019|Spring 2019]]<br />
*[[Applied/Physical_Applied_Math/Fall2018|Fall 2018]]<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=18271Applied/Physical Applied Math2019-10-29T08:54:14Z<p>Jeanluc: /* Fall 2019 */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a departmental meeting)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Sept. 5<br />
|<br />
|Organizational meeting<br />
|-<br />
|Sept. 12<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Sept. 19<br />
|Yu<br />
|Convection-induced singularity suppression in the Keller-Segel and other nonlinear PDEs<br />
|-<br />
|Sept. 26<br />
|Son<br />
|State-constraint static Hamilton-Jacobi equations in nested domains<br />
|-<br />
|Oct. 3<br />
|Hongfei<br />
|Microswimmers interacting with walls<br />
|-<br />
|Oct. 10<br />
|Alex Townsend<br />
|The ultraspherical spectral method<br />
|-<br />
|Oct. 17<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Oct. 24<br />
|Prerna<br />
||Pak, Feng and Stone, [https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/viscous-marangoni-migration-of-a-drop-in-a-poiseuille-flow-at-low-surface-peclet-numbers/2504CA0D4BC84B06E2E33DA39DE93355 Viscous Marangoni migration of a drop in a Poiseuille flow at low surface Péclet numbers].<br />
|-<br />
|Oct. 31<br />
|''no meeting''<br />
|<br />
|-<br />
|Nov. 7<br />
|Bryan<br />
|<br />
|-<br />
|Nov. 11<br />
|<br />
|<br />
|-<br />
|Nov. 14<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Nov. 21<br />
|<br />
|Practice talks for DFD<br />
|-<br />
|Dec. 5<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Dec. 12<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|}<br />
<br />
== Spring 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 24<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Jan. 31<br />
|Jean-Luc<br />
|Organizational meeting; J-LT speaks on Vortices in a channel<br />
|-<br />
|Feb. 7<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 14<br />
|Yu<br />
|Suppression of phase separation by mixing<br />
|-<br />
|Feb. 21<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 28<br />
|Bryan<br />
|Riffles shuffles and mixing<br />
|-<br />
|Mar. 7<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Mar. 14<br />
|Hongfei<br />
|[https://www.springer.com/us/book/9781441916044 Diffusion across potential barriers]<br />
|-<br />
|Mar. 21<br />
|<br />
|''Spring Break''<br />
|-<br />
|Mar. 28<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 4<br />
|Ruojun<br />
|Internal diffusion-limited aggregation and rotor-router walks with drift<br />
|-<br />
|Apr. 11<br />
|Jiajia<br />
|[https://doi.org/10.1063/1.1675038 Freed, Wiener Integrals and Models of Stiff Polymer Chains]<br />
|-<br />
|Apr. 18<br />
|Wangping<br />
|Entanglement of frictionless strings<br />
|-<br />
|Apr. 25<br />
|John<br />
|pseudo-Anosov homeomorphisms with large entropy<br />
|-<br />
|May 2<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|May 9<br />
|Saverio<br />
|Internal capillary origami (see [https://journals.aps.org/pra/abstract/10.1103/PhysRevA.44.1182 Seifert et al, Shape transformations of vesicles] and [https://www.annualreviews.org/doi/full/10.1146/annurev-fluid-122316-050130?casa_token=lYj2Hmpn0fEAAAAA:269tjv-n7Odyzgam7PniTi5WmNPjP0qVrO7qxV0a8Ox_Tl4fNsawlxTves-ev7vI_h9Sx_0jKfwK Bico et al., Elastocapillarity (Review article)])<br />
|-<br />
|}<br />
<br />
== Fall 2018 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 31<br />
|Jean-Luc<br />
|Organizational meeting; J-LT speaks on Aldous and Diaconis, [https://www.ams.org/journals/bull/1999-36-04/S0273-0979-99-00796-X/ Longest increasing subsequences: from patience sorting to the Baik-Deift-Johansson theorem]<br />
|-<br />
|Sep. 13<br />
|Son<br />
|[https://arxiv.org/abs/1808.06129 Rate of convergence for periodic homogenization of convex Hamilton-Jacobi equations in one dimension]<br />
|-<br />
|Sep. 20<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Sep. 27<br />
|[https://www.math.cmu.edu/~gautam/sj/index.html Gautam Iyer] (CMU)<br />
|[https://arxiv.org/abs/1806.03699 Dissipation enhancement by mixing]<br />
|-<br />
|Oct. 4<br />
|Gage<br />
|[https://www.dropbox.com/s/tjc4v03cwgzeppm/Group_talk_ab___notes.pdf Escape rates of random walks on free groups]<br />
|-<br />
|Oct. 11<br />
|<i>cancelled</i><br />
|<br />
|-<br />
|Oct. 18<br />
|Yu Feng<br />
|Relaxation enhancement for Advective Cahn-Hilliard (practice for specialty)<br />
|-<br />
|Oct. 25<br />
|Yu's specialty <b>2-3pm, B139</b><br />
|Relaxation enhancement for Advective Cahn-Hilliard<br />
|-<br />
|Nov. 1<br />
|Wil<br />
|Powers, [https://journals.aps.org/rmp/abstract/10.1103/RevModPhys.82.1607; Dynamics of filaments and membranes in a viscous fluid]; Guven et al. [http://iopscience.iop.org/article/10.1088/1751-8113/47/35/355201/pdf Environmental bias and elastic curves on surfaces]<br />
|-<br />
|Nov. 8<br />
|Tom<br />
|[https://arxiv.org/abs/1809.01190 Mixing by jellyfish]<br />
|-<br />
|Nov. 15<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Nov. 22<br />
|<br />
|''Thanksgiving Break''<br />
|-<br />
|Nov. 29<br />
|Chris<br />
|Sun et al., [https://www.sciencedirect.com/science/article/pii/S0167278911001588 A mathematical model for the synchronization of cows]<br />
|-<br />
|Dec. 6<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|'''Dec. 12, B239'''<br />
|Jean-Luc<br />
|Cooking food by flipping<br />
|-<br />
|Dec. 13<br />
|<br />
|''Faculty Meeting''<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absF19&diff=18238Applied/ACMS/absF192019-10-24T08:16:28Z<p>Jeanluc: /* Jean-Luc Thiffeault */</p>
<hr />
<div>= ACMS Abstracts: Fall 2019 =<br />
<br />
=== Leonardo Andrés Zepeda Núñez ===<br />
<br />
Title: Deep Learning for Electronic Structure Computations: A Tale of Symmetries, Locality, and Physics<br />
<br />
Abstract: Recently, the surge of interest in deep neural learning has dramatically improved image and signal processing, which has fueled breakthroughs in many domains such as drug discovery, genomics, and automatic translation. These advances have been further applied to scientific computing and, in particular, to electronic structure computations. In this case, the main objective is to directly compute the electron density, which encodes most of information of the system, thus bypassing the computationally intensive solution of the Kohn-Sham equations. However, similar to neural networks for image processing, the performance of the methods depends spectacularly on the physical and analytical intuition incorporated in the network, and on the training stage.<br />
<br />
In this talk, I will show how to build a network that respects physical symmetries and locality. I will show how to train the networks and how such properties impact the performance of the resulting network. Finally, I will present several examples for small yet realistic chemical systems.<br />
<br />
<br />
=== Daniel Floryan (UW-Madison) ===<br />
<br />
Title: Flexible Inertial Swimmers<br />
<br />
Abstract: Inertial swimmers deform their bodies and fins to push against the water and propel themselves forward. The deformation is driven partly by active musculature, and partly by passive elasticity. The interaction between elasticity and hydrodynamics confers features on the swimmers not enjoyed by their rigid friends, for example, boosts in speed when flapping at certain frequencies. We explain the salient features of flexible swimmers by drawing ideas from airfoils, vibrating beams, and flags flapping in the wind. The presence of fluid drag has important consequences. We also explore optimal arrangements of flexibility. (It turns out that nature is quite good.)<br />
<br />
<br />
=== Jianfeng Lu (Duke) ===<br />
<br />
Title: How to ``localize" the computation?<br />
<br />
It is often desirable to restrict the numerical computation to a local <br />
region to achieve best balance between accuracy and affordability in scientific computing. It is important to avoid artifacts and guarantee predictable modelling while artificial boundary conditions have to be introduced to restrict the computation. In this talk, we will discuss some recent understanding on how to achieve such local computation in the context of topological edge states and elliptic random media.<br />
<br />
<br />
=== Mitch Bushuk (GFDL/Princeton) ===<br />
<br />
Title: Arctic Sea Ice Predictability in a Changing Cryosphere<br />
<br />
Abstract: Forty years of satellite observations have documented a striking decline in the areal extent of Arctic sea ice. The loss of sea ice has impacts on the climate system, human populations, ecosystems, and natural environments across a broad range of spatial and temporal scales. These changes have motivated significant research interest in the predictability and prediction of Arctic sea ice on seasonal-to-interannual timescales. In this talk, I will address two related questions: (1) What is the inherent predictability of Arctic sea ice and what physical mechanisms underlie this predictability? and (2) How can this knowledge be leveraged to improve operational sea ice predictions? I will present findings on the relative roles of the ocean, sea ice, and atmosphere in controlling Arctic sea ice predictability. I will also present evidence for an Arctic spring predictability barrier, which may impose a sharp limit on our ability to make skillful predictions of the summer sea ice minimum. <br />
<br />
<br />
=== Qin Li (UW-Madison) ===<br />
<br />
Title: The power of randomness in scientific computing<br />
<br />
Abstract: Most numerical methods in scientific computing are deterministic. Traditionally, accuracy has been the target while the cost was not the concern. However, in this era of big data, we incline to relax the strict requirements on the accuracy to reduce numerical cost. Introducing randomness in the numerical solvers could potentially speed up the computation significantly at small sacrifice of accuracy. In this talk, I'd like to show two concrete examples how this is done: first on random sketching in experimental design, and the second on numerical homgenization, hoping the discussion can shed light on potential other applications. Joint work with Ke Chen, Jianfeng Lu, Kit Newton and Stephen Wright.<br />
<br />
<br />
=== Joel Nishimura (Arizona State) ===<br />
<br />
Title: Random graph models with fixed degree sequences: choices, consequences and irreducibility proofs for sampling<br />
<br />
Abstract: Determining which features of an empirical graph are noteworthy frequently relies upon the ability to sample random graphs with constrained properties. Since empirical graphs have distinctive degree sequences, one of the most popular random graph models is the configuration model, which produces a graph uniformly at random from the set of graphs with a fixed degree sequence. While it is commonly treated as though there is only a single configuration model, one sampled via stub-matching, there are many, depending on whether self-loops and multiedges are allowed and whether edge stubs are labeled or not. We show, these different configuration models can lead to drastically, sometimes opposite, interpretations of empirical graphs. In order to sample from these different configuration models, we review and develop the underpinnings of Markov chain Monte Carlo methods based upon double-edge swaps. We also present new results on the irreducibility of the Markov chain for graphs with self-loops, either proving irreducibility or exactly characterizing the degree sequences for which the Markov chain is reducible. This work completes the study of the irreducibility of double edge-swap Markov chains (and the related Curveball Markov chain) for all combinations of allowing self-loops, multiple self-loops and/or multiedges. <br />
<br />
<br />
=== Alex Townsend (Cornell) ===<br />
<br />
Title: Why are so many matrices and tensors of low rank in computational mathematics?<br />
<br />
Abstract: Matrices and tensors that appear in computational mathematics are so often well-approximated by low-rank objects. Since random ("average") matrices are almost surely of full rank, mathematics needs to explain the abundance of low-rank structures. We will give various methodologies that allow one to begin to understand the prevalence of compressible matrices and tensors and we hope to reveal an underlying link between disparate applications. In particular, we will show how one can connect the singular values of a matrix with displacement structure to a rational approximation problem that highlights fundamental connections between polynomial interpolation, Krylov methods, and fast Toeplitz solvers.<br />
<br />
<br />
=== Prashant G. Mehta ===<br />
<br />
Title: What is the Lagrangian for Nonlinear Filtering?<br />
<br />
Abstract: There is a certain magic involved in recasting the equations in Physics, and the algorithms in Engineering, in variational terms. The most classical of these ‘magics’ is the Lagrange’s formulation of the Newtonian mechanics. An accessible modern take on all this and more appears in the February 19, 2019 issue of The New Yorker magazine: https://www.newyorker.com/science/elements/a-different-kind-of-theory-of-everything?reload=true <br />
<br />
My talk is concerned with a variational (optimal control type) formulation of the problem of nonlinear filtering/estimation. Such formulations are referred to as duality between optimal estimation and optimal control. The first duality principle appears in the seminal (1961) paper of Kalman-Bucy, where the problem of minimum variance estimation is shown to be dual to a linear quadratic optimal control problem. <br />
<br />
In my talk, I will describe a generalization of the Kalman-Bucy duality theory to nonlinear filtering. The generalization is an exact extension, in the sense that the dual optimal control problem has the same minimum variance structure for linear and nonlinear filtering problems. Kalman-Bucy’s classical result is shown to be a special case. During the talk, I will also attempt to review other types of duality relationships that have appeared over the years for the problem of linear and nonlinear filtering. <br />
<br />
This is joint work with Jin Won Kim and Sean Meyn. The talk is based on the following papers: https://arxiv.org/pdf/1903.11195.pdf and https://arxiv.org/pdf/1904.01710.pdf.<br />
<br />
<br />
=== Jean-Luc Thiffeault ===<br />
<br />
Title: Shape matters: A Brownian swimmer in a channel<br />
<br />
Abstract: We consider a simple model of a two-dimensional microswimmer with fixed swimming speed. The direction of swimming changes according to<br />
a Brownian process, and the swimmer is interacting with boundaries. This is a standard model for a simple microswimmer, or a confined<br />
wormlike chain polymer. The shape of the swimmer determines the range of allowable values that its degrees of freedom can assume --- its<br />
configuration space. Using natural assumptions about reflection of the swimmer at boundaries, we compute the swimmer's invariant<br />
distribution across a channel consisting of two parallel walls, and the statistics of spreading in the longitudinal direction. This gives<br />
us the effective diffusion constant of the swimmer's large scale motion. When the swimmer is longer than the channel width, it cannot<br />
reverse, and we then compute the mean drift velocity of the swimmer. This model offers insight into experiments of scattering of swimmers<br />
from boundaries, and serves as an exactly-solvable baseline when comparing to more complex models. This is joint work with Hongfei Chen.<br />
<br />
=== Tan Bui (UT-Austin) ===<br />
<br />
Title: Scalable Algorithms for Data-driven Inverse and Learning Problems<br />
<br />
Abstract: Inverse problems and uncertainty quantification (UQ) are pervasive in scientific discovery and decision-making for complex, natural, engineered, and societal systems. They are perhaps the most popular mathematical approaches for enabling predictive scientific simulations that integrate observational/experimental data, simulations and/or models. Unfortunately, inverse/UQ problems for practical complex systems possess these the simultaneous challenges: the large-scale forward problem challenge, the high dimensional parameter space challenge, and the big data challenge.<br />
<br />
To address the first challenge, we have developed parallel high-order (hybridized) discontinuous Galerkin methods to discretize complex forward PDEs. <br />
To address the second challenge, we have developed various approaches from model reduction to advanced Markov chain Monte Carlo methods to effectively explore high dimensional parameter spaces to compute posterior statistics. To address the last challenge, we have developed a randomized misfit approach that uncovers the interplay between the Johnson-Lindenstrauss and the Morozov's discrepancy principle to significantly reduce the dimension of the data without compromising the quality of the inverse solutions.<br />
<br />
In this talk we selectively present scalable and rigorous approaches to tackle these challenges for PDE-governed Bayesian inverse problems. Various numerical results for simple to complex PDEs will be presented to verify our algorithms and theoretical findings. If time permits, we will present our recent work on scientific machine learning for inverse and learning problems.</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=18114Applied/Physical Applied Math2019-10-07T13:55:15Z<p>Jeanluc: /* Fall 2019 */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a departmental meeting)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Sept. 5<br />
|<br />
|Organizational meeting<br />
|-<br />
|Sept. 12<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Sept. 19<br />
|Yu<br />
|Convection-induced singularity suppression in the Keller-Segel and other nonlinear PDEs<br />
|-<br />
|Sept. 26<br />
|Son<br />
|State-constraint static Hamilton-Jacobi equations in nested domains<br />
|-<br />
|Oct. 3<br />
|Hongfei<br />
|Microswimmers interacting with walls<br />
|-<br />
|Oct. 10<br />
|Alex Townsend<br />
|The ultraspherical spectral method<br />
|-<br />
|Oct. 17<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Oct. 24<br />
|Prerna<br />
|<br />
|-<br />
|Oct. 31<br />
|<br />
|<br />
|-<br />
|Nov. 7<br />
|Bryan<br />
|<br />
|-<br />
|Nov. 11<br />
|<br />
|<br />
|-<br />
|Nov. 14<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Nov. 21<br />
|<br />
|Practice talks for DFD<br />
|-<br />
|Dec. 5<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Dec. 12<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|}<br />
<br />
== Spring 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 24<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Jan. 31<br />
|Jean-Luc<br />
|Organizational meeting; J-LT speaks on Vortices in a channel<br />
|-<br />
|Feb. 7<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 14<br />
|Yu<br />
|Suppression of phase separation by mixing<br />
|-<br />
|Feb. 21<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 28<br />
|Bryan<br />
|Riffles shuffles and mixing<br />
|-<br />
|Mar. 7<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Mar. 14<br />
|Hongfei<br />
|[https://www.springer.com/us/book/9781441916044 Diffusion across potential barriers]<br />
|-<br />
|Mar. 21<br />
|<br />
|''Spring Break''<br />
|-<br />
|Mar. 28<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 4<br />
|Ruojun<br />
|Internal diffusion-limited aggregation and rotor-router walks with drift<br />
|-<br />
|Apr. 11<br />
|Jiajia<br />
|[https://doi.org/10.1063/1.1675038 Freed, Wiener Integrals and Models of Stiff Polymer Chains]<br />
|-<br />
|Apr. 18<br />
|Wangping<br />
|Entanglement of frictionless strings<br />
|-<br />
|Apr. 25<br />
|John<br />
|pseudo-Anosov homeomorphisms with large entropy<br />
|-<br />
|May 2<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|May 9<br />
|Saverio<br />
|Internal capillary origami (see [https://journals.aps.org/pra/abstract/10.1103/PhysRevA.44.1182 Seifert et al, Shape transformations of vesicles] and [https://www.annualreviews.org/doi/full/10.1146/annurev-fluid-122316-050130?casa_token=lYj2Hmpn0fEAAAAA:269tjv-n7Odyzgam7PniTi5WmNPjP0qVrO7qxV0a8Ox_Tl4fNsawlxTves-ev7vI_h9Sx_0jKfwK Bico et al., Elastocapillarity (Review article)])<br />
|-<br />
|}<br />
<br />
== Fall 2018 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 31<br />
|Jean-Luc<br />
|Organizational meeting; J-LT speaks on Aldous and Diaconis, [https://www.ams.org/journals/bull/1999-36-04/S0273-0979-99-00796-X/ Longest increasing subsequences: from patience sorting to the Baik-Deift-Johansson theorem]<br />
|-<br />
|Sep. 13<br />
|Son<br />
|[https://arxiv.org/abs/1808.06129 Rate of convergence for periodic homogenization of convex Hamilton-Jacobi equations in one dimension]<br />
|-<br />
|Sep. 20<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Sep. 27<br />
|[https://www.math.cmu.edu/~gautam/sj/index.html Gautam Iyer] (CMU)<br />
|[https://arxiv.org/abs/1806.03699 Dissipation enhancement by mixing]<br />
|-<br />
|Oct. 4<br />
|Gage<br />
|[https://www.dropbox.com/s/tjc4v03cwgzeppm/Group_talk_ab___notes.pdf Escape rates of random walks on free groups]<br />
|-<br />
|Oct. 11<br />
|<i>cancelled</i><br />
|<br />
|-<br />
|Oct. 18<br />
|Yu Feng<br />
|Relaxation enhancement for Advective Cahn-Hilliard (practice for specialty)<br />
|-<br />
|Oct. 25<br />
|Yu's specialty <b>2-3pm, B139</b><br />
|Relaxation enhancement for Advective Cahn-Hilliard<br />
|-<br />
|Nov. 1<br />
|Wil<br />
|Powers, [https://journals.aps.org/rmp/abstract/10.1103/RevModPhys.82.1607; Dynamics of filaments and membranes in a viscous fluid]; Guven et al. [http://iopscience.iop.org/article/10.1088/1751-8113/47/35/355201/pdf Environmental bias and elastic curves on surfaces]<br />
|-<br />
|Nov. 8<br />
|Tom<br />
|[https://arxiv.org/abs/1809.01190 Mixing by jellyfish]<br />
|-<br />
|Nov. 15<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Nov. 22<br />
|<br />
|''Thanksgiving Break''<br />
|-<br />
|Nov. 29<br />
|Chris<br />
|Sun et al., [https://www.sciencedirect.com/science/article/pii/S0167278911001588 A mathematical model for the synchronization of cows]<br />
|-<br />
|Dec. 6<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|'''Dec. 12, B239'''<br />
|Jean-Luc<br />
|Cooking food by flipping<br />
|-<br />
|Dec. 13<br />
|<br />
|''Faculty Meeting''<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=18087Applied/ACMS2019-10-02T12:14:48Z<p>Jeanluc: /* Fall 2019 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Sept 6<br />
|[http://math.mit.edu/~lzepeda/ Leonardo Andrés Zepeda Núñez] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Leonardo Andrés Zepeda Núñez (UW-Madison)|Deep Learning for Electronic Structure Computations: A Tale of Symmetries, Locality, and Physics]]''<br />
| Li<br />
|-<br />
| Sept 13<br />
|[http://dfloryan.mycpanel.princeton.edu/ Daniel Floryan] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Daniel Floryan (UW-Madison)|Flexible Inertial Swimmers]]''<br />
| Jean-Luc<br />
|-<br />
| Sept 14-15<br />
|[https://www.ams.org/meetings/sectional/2267_program.html AMS sectional meeting]<br />
| UW-Madison<br />
|-<br />
| Sept 20<br />
|[https://www.gfdl.noaa.gov/mitch-bushuk/ Mitch Bushuk] (GFDL/Princeton)<br />
|''[[Applied/ACMS/absF19#Mitch Bushuk (GFDL/Princeton)|Arctic Sea Ice Predictability in a Changing Cryosphere]]''<br />
| Chen<br />
|-<br />
| Sept 20 (colloquium, 4pm, B239)<br />
|[https://services.math.duke.edu/~jianfeng/ Jianfeng Lu] (Duke)<br />
|''[[Applied/ACMS/absF19#Jianfeng Lu (Duke)|How to "localize" the computation?]]''<br />
| Li<br />
|-<br />
| Sept 27<br />
|[http://www.math.wisc.edu/~qinli/ Qin Li] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Qin Li (UW-Madison)|The power of randomness in scientific computing]]''<br />
| host<br />
|-<br />
| Oct 4<br />
|[https://isearch.asu.edu/profile/2169104 Joel Nishimura] (Arizona State)<br />
|''[[Applied/ACMS/absF19#Joel Nishimura (Arizona State)|Random graph models with fixed degree sequences: choices, consequences and irreducibility proofs for sampling]]''<br />
| Cochran<br />
|-<br />
| Oct 11<br />
|[http://pi.math.cornell.edu/~ajt/ Alex Townsend] (Cornell)<br />
|''[[Applied/ACMS/absF19#Alex Townsend (Cornell)|TBA]]''<br />
| Li<br />
|-<br />
| Oct 18<br />
|[http://mehta.mechse.illinois.edu/ Prashant G. Mehta] (UIUC)<br />
|''[[Applied/ACMS/absF19#Prashant G. Mehta (UIUC)|What is the Lagrangian for Nonlinear Filtering?]]''<br />
| Chen<br />
|-<br />
| Oct 25<br />
|[https://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Jean-Luc Thiffeault|Shape matters: A Brownian microswimmer interacting with walls]]''<br />
| <br />
|-<br />
| Nov 1<br />
|[https://users.oden.utexas.edu/~tanbui/ Tan Bui] (UT-Austin)<br />
|''[[Applied/ACMS/absF19#Tan Bui (UT-Austin)|Title: TBA]]''<br />
| Li<br />
|-<br />
| Nov 8<br />
|[https://pan.labs.wisc.edu/staff/pan-wenxiao/ Wenxiao Pan] (UW)<br />
|''[[Applied/ACMS/absF19#Wenxiao Pan (UW)|TBA]]''<br />
| Spagnolie<br />
| <br />
|-<br />
| Nov 15<br />
|[https://www.math.wisc.edu/~pgera/ Prerna Gera] (UW)<br />
|''[[Applied/ACMS/absF19#Prerna Gera (UW)|TBA]]''<br />
| Spagnolie<br />
|-<br />
| Dec 6<br />
|[https://math.berkeley.edu/~linlin/ Lin Lin] (Berkeley)<br />
|''[[Applied/ACMS/absF19#Lin Lin (UC Berkeley)|TBA]]''<br />
| Li<br />
|-<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
*[[Applied/ACMS/Spring2020|Spring 2020]]<br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absF19&diff=18086Applied/ACMS/absF192019-10-02T12:12:34Z<p>Jeanluc: /* ACMS Abstracts: Fall 2019 */</p>
<hr />
<div>= ACMS Abstracts: Fall 2019 =<br />
<br />
=== Leonardo Andrés Zepeda Núñez ===<br />
<br />
Title: Deep Learning for Electronic Structure Computations: A Tale of Symmetries, Locality, and Physics<br />
<br />
Abstract: Recently, the surge of interest in deep neural learning has dramatically improved image and signal processing, which has fueled breakthroughs in many domains such as drug discovery, genomics, and automatic translation. These advances have been further applied to scientific computing and, in particular, to electronic structure computations. In this case, the main objective is to directly compute the electron density, which encodes most of information of the system, thus bypassing the computationally intensive solution of the Kohn-Sham equations. However, similar to neural networks for image processing, the performance of the methods depends spectacularly on the physical and analytical intuition incorporated in the network, and on the training stage.<br />
<br />
In this talk, I will show how to build a network that respects physical symmetries and locality. I will show how to train the networks and how such properties impact the performance of the resulting network. Finally, I will present several examples for small yet realistic chemical systems.<br />
<br />
<br />
=== Daniel Floryan (UW-Madison) ===<br />
<br />
Title: Flexible Inertial Swimmers<br />
<br />
Abstract: Inertial swimmers deform their bodies and fins to push against the water and propel themselves forward. The deformation is driven partly by active musculature, and partly by passive elasticity. The interaction between elasticity and hydrodynamics confers features on the swimmers not enjoyed by their rigid friends, for example, boosts in speed when flapping at certain frequencies. We explain the salient features of flexible swimmers by drawing ideas from airfoils, vibrating beams, and flags flapping in the wind. The presence of fluid drag has important consequences. We also explore optimal arrangements of flexibility. (It turns out that nature is quite good.)<br />
<br />
<br />
=== Jianfeng Lu (Duke) ===<br />
<br />
Title: How to ``localize" the computation?<br />
<br />
It is often desirable to restrict the numerical computation to a local <br />
region to achieve best balance between accuracy and affordability in scientific computing. It is important to avoid artifacts and guarantee predictable modelling while artificial boundary conditions have to be introduced to restrict the computation. In this talk, we will discuss some recent understanding on how to achieve such local computation in the context of topological edge states and elliptic random media.<br />
<br />
<br />
=== Mitch Bushuk (GFDL/Princeton) ===<br />
<br />
Title: Arctic Sea Ice Predictability in a Changing Cryosphere<br />
<br />
Abstract: Forty years of satellite observations have documented a striking decline in the areal extent of Arctic sea ice. The loss of sea ice has impacts on the climate system, human populations, ecosystems, and natural environments across a broad range of spatial and temporal scales. These changes have motivated significant research interest in the predictability and prediction of Arctic sea ice on seasonal-to-interannual timescales. In this talk, I will address two related questions: (1) What is the inherent predictability of Arctic sea ice and what physical mechanisms underlie this predictability? and (2) How can this knowledge be leveraged to improve operational sea ice predictions? I will present findings on the relative roles of the ocean, sea ice, and atmosphere in controlling Arctic sea ice predictability. I will also present evidence for an Arctic spring predictability barrier, which may impose a sharp limit on our ability to make skillful predictions of the summer sea ice minimum. <br />
<br />
<br />
=== Qin Li (UW-Madison) ===<br />
<br />
Title: The power of randomness in scientific computing<br />
<br />
Abstract: Most numerical methods in scientific computing are deterministic. Traditionally, accuracy has been the target while the cost was not the concern. However, in this era of big data, we incline to relax the strict requirements on the accuracy to reduce numerical cost. Introducing randomness in the numerical solvers could potentially speed up the computation significantly at small sacrifice of accuracy. In this talk, I'd like to show two concrete examples how this is done: first on random sketching in experimental design, and the second on numerical homgenization, hoping the discussion can shed light on potential other applications. Joint work with Ke Chen, Jianfeng Lu, Kit Newton and Stephen Wright.<br />
<br />
<br />
=== Joel Nishimura (Arizona State) ===<br />
<br />
Title: Random graph models with fixed degree sequences: choices, consequences and irreducibility proofs for sampling<br />
<br />
Abstract: Determining which features of an empirical graph are noteworthy frequently relies upon the ability to sample random graphs with constrained properties. Since empirical graphs have distinctive degree sequences, one of the most popular random graph models is the configuration model, which produces a graph uniformly at random from the set of graphs with a fixed degree sequence. While it is commonly treated as though there is only a single configuration model, one sampled via stub-matching, there are many, depending on whether self-loops and multiedges are allowed and whether edge stubs are labeled or not. We show, these different configuration models can lead to drastically, sometimes opposite, interpretations of empirical graphs. In order to sample from these different configuration models, we review and develop the underpinnings of Markov chain Monte Carlo methods based upon double-edge swaps. We also present new results on the irreducibility of the Markov chain for graphs with self-loops, either proving irreducibility or exactly characterizing the degree sequences for which the Markov chain is reducible. This work completes the study of the irreducibility of double edge-swap Markov chains (and the related Curveball Markov chain) for all combinations of allowing self-loops, multiple self-loops and/or multiedges. <br />
<br />
<br />
=== Prashant G. Mehta ===<br />
<br />
Title: What is the Lagrangian for Nonlinear Filtering?<br />
<br />
Abstract: There is a certain magic involved in recasting the equations in Physics, and the algorithms in Engineering, in variational terms. The most classical of these ‘magics’ is the Lagrange’s formulation of the Newtonian mechanics. An accessible modern take on all this and more appears in the February 19, 2019 issue of The New Yorker magazine: https://www.newyorker.com/science/elements/a-different-kind-of-theory-of-everything?reload=true <br />
<br />
My talk is concerned with a variational (optimal control type) formulation of the problem of nonlinear filtering/estimation. Such formulations are referred to as duality between optimal estimation and optimal control. The first duality principle appears in the seminal (1961) paper of Kalman-Bucy, where the problem of minimum variance estimation is shown to be dual to a linear quadratic optimal control problem. <br />
<br />
In my talk, I will describe a generalization of the Kalman-Bucy duality theory to nonlinear filtering. The generalization is an exact extension, in the sense that the dual optimal control problem has the same minimum variance structure for linear and nonlinear filtering problems. Kalman-Bucy’s classical result is shown to be a special case. During the talk, I will also attempt to review other types of duality relationships that have appeared over the years for the problem of linear and nonlinear filtering. <br />
<br />
This is joint work with Jin Won Kim and Sean Meyn. The talk is based on the following papers: https://arxiv.org/pdf/1903.11195.pdf and https://arxiv.org/pdf/1904.01710.pdf.<br />
<br />
<br />
=== Jean-Luc Thiffeault ===<br />
<br />
We consider a simple model of a two-dimensional microswimmer with fixed swimming speed. The direction of swimming changes according to<br />
a Brownian process, and the swimmer is interacting with boundaries. This is a standard model for a simple microswimmer, or a confined<br />
wormlike chain polymer. The shape of the swimmer determines the range of allowable values that its degrees of freedom can assume --- its<br />
configuration space. Using natural assumptions about reflection of the swimmer at boundaries, we compute the swimmer's invariant<br />
distribution across a channel consisting of two parallel walls, and the statistics of spreading in the longitudinal direction. This gives<br />
us the effective diffusion constant of the swimmer's large scale motion. When the swimmer is longer than the channel width, it cannot<br />
reverse, and we then compute the mean drift velocity of the swimmer. This model offers insight into experiments of scattering of swimmers<br />
from boundaries, and serves as an exactly-solvable baseline when comparing to more complex models. This is joint work with Hongfei Chen.</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absF19&diff=18085Applied/ACMS/absF192019-10-02T12:11:29Z<p>Jeanluc: /* ACMS Abstracts: Fall 2019 */</p>
<hr />
<div>= ACMS Abstracts: Fall 2019 =<br />
<br />
=== Leonardo Andrés Zepeda Núñez ===<br />
<br />
Title: Deep Learning for Electronic Structure Computations: A Tale of Symmetries, Locality, and Physics<br />
<br />
Abstract: Recently, the surge of interest in deep neural learning has dramatically improved image and signal processing, which has fueled breakthroughs in many domains such as drug discovery, genomics, and automatic translation. These advances have been further applied to scientific computing and, in particular, to electronic structure computations. In this case, the main objective is to directly compute the electron density, which encodes most of information of the system, thus bypassing the computationally intensive solution of the Kohn-Sham equations. However, similar to neural networks for image processing, the performance of the methods depends spectacularly on the physical and analytical intuition incorporated in the network, and on the training stage.<br />
<br />
In this talk, I will show how to build a network that respects physical symmetries and locality. I will show how to train the networks and how such properties impact the performance of the resulting network. Finally, I will present several examples for small yet realistic chemical systems.<br />
<br />
<br />
=== Daniel Floryan (UW-Madison) ===<br />
<br />
Title: Flexible Inertial Swimmers<br />
<br />
Abstract: Inertial swimmers deform their bodies and fins to push against the water and propel themselves forward. The deformation is driven partly by active musculature, and partly by passive elasticity. The interaction between elasticity and hydrodynamics confers features on the swimmers not enjoyed by their rigid friends, for example, boosts in speed when flapping at certain frequencies. We explain the salient features of flexible swimmers by drawing ideas from airfoils, vibrating beams, and flags flapping in the wind. The presence of fluid drag has important consequences. We also explore optimal arrangements of flexibility. (It turns out that nature is quite good.)<br />
<br />
<br />
=== Jianfeng Lu (Duke) ===<br />
<br />
Title: How to ``localize" the computation?<br />
<br />
It is often desirable to restrict the numerical computation to a local <br />
region to achieve best balance between accuracy and affordability in scientific computing. It is important to avoid artifacts and guarantee predictable modelling while artificial boundary conditions have to be introduced to restrict the computation. In this talk, we will discuss some recent understanding on how to achieve such local computation in the context of topological edge states and elliptic random media.<br />
<br />
<br />
=== Mitch Bushuk (GFDL/Princeton) ===<br />
<br />
Title: Arctic Sea Ice Predictability in a Changing Cryosphere<br />
<br />
Abstract: Forty years of satellite observations have documented a striking decline in the areal extent of Arctic sea ice. The loss of sea ice has impacts on the climate system, human populations, ecosystems, and natural environments across a broad range of spatial and temporal scales. These changes have motivated significant research interest in the predictability and prediction of Arctic sea ice on seasonal-to-interannual timescales. In this talk, I will address two related questions: (1) What is the inherent predictability of Arctic sea ice and what physical mechanisms underlie this predictability? and (2) How can this knowledge be leveraged to improve operational sea ice predictions? I will present findings on the relative roles of the ocean, sea ice, and atmosphere in controlling Arctic sea ice predictability. I will also present evidence for an Arctic spring predictability barrier, which may impose a sharp limit on our ability to make skillful predictions of the summer sea ice minimum. <br />
<br />
<br />
=== Qin Li (UW-Madison) ===<br />
<br />
Title: The power of randomness in scientific computing<br />
<br />
Abstract: Most numerical methods in scientific computing are deterministic. Traditionally, accuracy has been the target while the cost was not the concern. However, in this era of big data, we incline to relax the strict requirements on the accuracy to reduce numerical cost. Introducing randomness in the numerical solvers could potentially speed up the computation significantly at small sacrifice of accuracy. In this talk, I'd like to show two concrete examples how this is done: first on random sketching in experimental design, and the second on numerical homgenization, hoping the discussion can shed light on potential other applications. Joint work with Ke Chen, Jianfeng Lu, Kit Newton and Stephen Wright.<br />
<br />
<br />
=== Joel Nishimura (Arizona State) ===<br />
<br />
Title: Random graph models with fixed degree sequences: choices, consequences and irreducibility proofs for sampling<br />
<br />
Abstract: Determining which features of an empirical graph are noteworthy frequently relies upon the ability to sample random graphs with constrained properties. Since empirical graphs have distinctive degree sequences, one of the most popular random graph models is the configuration model, which produces a graph uniformly at random from the set of graphs with a fixed degree sequence. While it is commonly treated as though there is only a single configuration model, one sampled via stub-matching, there are many, depending on whether self-loops and multiedges are allowed and whether edge stubs are labeled or not. We show, these different configuration models can lead to drastically, sometimes opposite, interpretations of empirical graphs. In order to sample from these different configuration models, we review and develop the underpinnings of Markov chain Monte Carlo methods based upon double-edge swaps. We also present new results on the irreducibility of the Markov chain for graphs with self-loops, either proving irreducibility or exactly characterizing the degree sequences for which the Markov chain is reducible. This work completes the study of the irreducibility of double edge-swap Markov chains (and the related Curveball Markov chain) for all combinations of allowing self-loops, multiple self-loops and/or multiedges. <br />
<br />
<br />
=== Prashant G. Mehta ===<br />
<br />
Title: What is the Lagrangian for Nonlinear Filtering?<br />
<br />
Abstract: There is a certain magic involved in recasting the equations in Physics, and the algorithms in Engineering, in variational terms. The most classical of these ‘magics’ is the Lagrange’s formulation of the Newtonian mechanics. An accessible modern take on all this and more appears in the February 19, 2019 issue of The New Yorker magazine: https://www.newyorker.com/science/elements/a-different-kind-of-theory-of-everything?reload=true <br />
<br />
My talk is concerned with a variational (optimal control type) formulation of the problem of nonlinear filtering/estimation. Such formulations are referred to as duality between optimal estimation and optimal control. The first duality principle appears in the seminal (1961) paper of Kalman-Bucy, where the problem of minimum variance estimation is shown to be dual to a linear quadratic optimal control problem. <br />
<br />
In my talk, I will describe a generalization of the Kalman-Bucy duality theory to nonlinear filtering. The generalization is an exact extension, in the sense that the dual optimal control problem has the same minimum variance structure for linear and nonlinear filtering problems. Kalman-Bucy’s classical result is shown to be a special case. During the talk, I will also attempt to review other types of duality relationships that have appeared over the years for the problem of linear and nonlinear filtering. <br />
<br />
This is joint work with Jin Won Kim and Sean Meyn. The talk is based on the following papers: https://arxiv.org/pdf/1903.11195.pdf and https://arxiv.org/pdf/1904.01710.pdf.<br />
<br />
<br />
=== Jean-Luc Thiffeault (UW-Madison) ===<br />
<br />
We consider a simple model of a two-dimensional microswimmer with fixed swimming speed. The direction of swimming changes according to<br />
a Brownian process, and the swimmer is interacting with boundaries. This is a standard model for a simple microswimmer, or a confined<br />
wormlike chain polymer. The shape of the swimmer determines the range of allowable values that its degrees of freedom can assume --- its<br />
configuration space. Using natural assumptions about reflection of the swimmer at boundaries, we compute the swimmer's invariant<br />
distribution across a channel consisting of two parallel walls, and the statistics of spreading in the longitudinal direction. This gives<br />
us the effective diffusion constant of the swimmer's large scale motion. When the swimmer is longer than the channel width, it cannot<br />
reverse, and we then compute the mean drift velocity of the swimmer. This model offers insight into experiments of scattering of swimmers<br />
from boundaries, and serves as an exactly-solvable baseline when comparing to more complex models. This is joint work with Hongfei Chen.</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=18084Applied/ACMS2019-10-02T12:08:39Z<p>Jeanluc: /* Fall 2019 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Sept 6<br />
|[http://math.mit.edu/~lzepeda/ Leonardo Andrés Zepeda Núñez] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Leonardo Andrés Zepeda Núñez (UW-Madison)|Deep Learning for Electronic Structure Computations: A Tale of Symmetries, Locality, and Physics]]''<br />
| Li<br />
|-<br />
| Sept 13<br />
|[http://dfloryan.mycpanel.princeton.edu/ Daniel Floryan] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Daniel Floryan (UW-Madison)|Flexible Inertial Swimmers]]''<br />
| Jean-Luc<br />
|-<br />
| Sept 14-15<br />
|[https://www.ams.org/meetings/sectional/2267_program.html AMS sectional meeting]<br />
| UW-Madison<br />
|-<br />
| Sept 20<br />
|[https://www.gfdl.noaa.gov/mitch-bushuk/ Mitch Bushuk] (GFDL/Princeton)<br />
|''[[Applied/ACMS/absF19#Mitch Bushuk (GFDL/Princeton)|Arctic Sea Ice Predictability in a Changing Cryosphere]]''<br />
| Chen<br />
|-<br />
| Sept 20 (colloquium, 4pm, B239)<br />
|[https://services.math.duke.edu/~jianfeng/ Jianfeng Lu] (Duke)<br />
|''[[Applied/ACMS/absF19#Jianfeng Lu (Duke)|How to "localize" the computation?]]''<br />
| Li<br />
|-<br />
| Sept 27<br />
|[http://www.math.wisc.edu/~qinli/ Qin Li] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Qin Li (UW-Madison)|The power of randomness in scientific computing]]''<br />
| host<br />
|-<br />
| Oct 4<br />
|[https://isearch.asu.edu/profile/2169104 Joel Nishimura] (Arizona State)<br />
|''[[Applied/ACMS/absF19#Joel Nishimura (Arizona State)|Random graph models with fixed degree sequences: choices, consequences and irreducibility proofs for sampling]]''<br />
| Cochran<br />
|-<br />
| Oct 11<br />
|[http://pi.math.cornell.edu/~ajt/ Alex Townsend] (Cornell)<br />
|''[[Applied/ACMS/absF19#Alex Townsend (Cornell)|TBA]]''<br />
| Li<br />
|-<br />
| Oct 18<br />
|[http://mehta.mechse.illinois.edu/ Prashant G. Mehta] (UIUC)<br />
|''[[Applied/ACMS/absF19#Prashant G. Mehta (UIUC)|Title: What is the Lagrangian for Nonlinear Filtering?]]''<br />
| Chen<br />
|-<br />
| Oct 25<br />
|[https://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault] (UW-Madison)<br />
|''[[Applied/ACMS/absF19# Jean-Luc Thiffeault|Shape matters: A Brownian microswimmer interacting with walls]]''<br />
| <br />
|-<br />
| Nov 1<br />
|[https://users.oden.utexas.edu/~tanbui/ Tan Bui] (UT-Austin)<br />
|''[[Applied/ACMS/absF19#Tan Bui (UT-Austin)|Title: TBA]]''<br />
| Li<br />
|-<br />
| Nov 8<br />
|[https://pan.labs.wisc.edu/staff/pan-wenxiao/ Wenxiao Pan] (UW)<br />
|''[[Applied/ACMS/absF19#Wenxiao Pan (UW)|TBA]]''<br />
| Spagnolie<br />
| <br />
|-<br />
| Nov 15<br />
|[https://www.math.wisc.edu/~pgera/ Prerna Gera] (UW)<br />
|''[[Applied/ACMS/absF19#Prerna Gera (UW)|TBA]]''<br />
| Spagnolie<br />
|-<br />
| Dec 6<br />
|[https://math.berkeley.edu/~linlin/ Lin Lin] (Berkeley)<br />
|''[[Applied/ACMS/absF19#Lin Lin (UC Berkeley)|TBA]]''<br />
| Li<br />
|-<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
*[[Applied/ACMS/Spring2020|Spring 2020]]<br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absF19&diff=18058Applied/ACMS/absF192019-10-01T12:57:33Z<p>Jeanluc: /* ACMS Abstracts: Fall 2019 */</p>
<hr />
<div>= ACMS Abstracts: Fall 2019 =<br />
<br />
=== Leonardo Andrés Zepeda Núñez ===<br />
<br />
Title: Deep Learning for Electronic Structure Computations: A Tale of Symmetries, Locality, and Physics<br />
<br />
Abstract: Recently, the surge of interest in deep neural learning has dramatically improved image and signal processing, which has fueled breakthroughs in many domains such as drug discovery, genomics, and automatic translation. These advances have been further applied to scientific computing and, in particular, to electronic structure computations. In this case, the main objective is to directly compute the electron density, which encodes most of information of the system, thus bypassing the computationally intensive solution of the Kohn-Sham equations. However, similar to neural networks for image processing, the performance of the methods depends spectacularly on the physical and analytical intuition incorporated in the network, and on the training stage.<br />
<br />
In this talk, I will show how to build a network that respects physical symmetries and locality. I will show how to train the networks and how such properties impact the performance of the resulting network. Finally, I will present several examples for small yet realistic chemical systems.<br />
<br />
<br />
=== Daniel Floryan (UW-Madison) ===<br />
<br />
Title: Flexible Inertial Swimmers<br />
<br />
Abstract: Inertial swimmers deform their bodies and fins to push against the water and propel themselves forward. The deformation is driven partly by active musculature, and partly by passive elasticity. The interaction between elasticity and hydrodynamics confers features on the swimmers not enjoyed by their rigid friends, for example, boosts in speed when flapping at certain frequencies. We explain the salient features of flexible swimmers by drawing ideas from airfoils, vibrating beams, and flags flapping in the wind. The presence of fluid drag has important consequences. We also explore optimal arrangements of flexibility. (It turns out that nature is quite good.)<br />
<br />
<br />
=== Jianfeng Lu (Duke) ===<br />
<br />
Title: How to ``localize" the computation?<br />
<br />
It is often desirable to restrict the numerical computation to a local <br />
region to achieve best balance between accuracy and affordability in scientific computing. It is important to avoid artifacts and guarantee predictable modelling while artificial boundary conditions have to be introduced to restrict the computation. In this talk, we will discuss some recent understanding on how to achieve such local computation in the context of topological edge states and elliptic random media.<br />
<br />
<br />
=== Mitch Bushuk (GFDL/Princeton) ===<br />
<br />
Title: Arctic Sea Ice Predictability in a Changing Cryosphere<br />
<br />
Abstract: Forty years of satellite observations have documented a striking decline in the areal extent of Arctic sea ice. The loss of sea ice has impacts on the climate system, human populations, ecosystems, and natural environments across a broad range of spatial and temporal scales. These changes have motivated significant research interest in the predictability and prediction of Arctic sea ice on seasonal-to-interannual timescales. In this talk, I will address two related questions: (1) What is the inherent predictability of Arctic sea ice and what physical mechanisms underlie this predictability? and (2) How can this knowledge be leveraged to improve operational sea ice predictions? I will present findings on the relative roles of the ocean, sea ice, and atmosphere in controlling Arctic sea ice predictability. I will also present evidence for an Arctic spring predictability barrier, which may impose a sharp limit on our ability to make skillful predictions of the summer sea ice minimum. <br />
<br />
<br />
=== Qin Li (UW-Madison) ===<br />
<br />
Title: The power of randomness in scientific computing<br />
<br />
Abstract: Most numerical methods in scientific computing are deterministic. Traditionally, accuracy has been the target while the cost was not the concern. However, in this era of big data, we incline to relax the strict requirements on the accuracy to reduce numerical cost. Introducing randomness in the numerical solvers could potentially speed up the computation significantly at small sacrifice of accuracy. In this talk, I'd like to show two concrete examples how this is done: first on random sketching in experimental design, and the second on numerical homgenization, hoping the discussion can shed light on potential other applications. Joint work with Ke Chen, Jianfeng Lu, Kit Newton and Stephen Wright.<br />
<br />
<br />
=== Joel Nishimura (Arizona State) ===<br />
<br />
Title: Random graph models with fixed degree sequences: choices, consequences and irreducibility proofs for sampling<br />
<br />
Abstract: Determining which features of an empirical graph are noteworthy frequently relies upon the ability to sample random graphs with constrained properties. Since empirical graphs have distinctive degree sequences, one of the most popular random graph models is the configuration model, which produces a graph uniformly at random from the set of graphs with a fixed degree sequence. While it is commonly treated as though there is only a single configuration model, one sampled via stub-matching, there are many, depending on whether self-loops and multiedges are allowed and whether edge stubs are labeled or not. We show, these different configuration models can lead to drastically, sometimes opposite, interpretations of empirical graphs. In order to sample from these different configuration models, we review and develop the underpinnings of Markov chain Monte Carlo methods based upon double-edge swaps. We also present new results on the irreducibility of the Markov chain for graphs with self-loops, either proving irreducibility or exactly characterizing the degree sequences for which the Markov chain is reducible. This work completes the study of the irreducibility of double edge-swap Markov chains (and the related Curveball Markov chain) for all combinations of allowing self-loops, multiple self-loops and/or multiedges. <br />
<br />
<br />
=== Prashant G. Mehta ===<br />
<br />
Title: What is the Lagrangian for Nonlinear Filtering?<br />
<br />
Abstract: There is a certain magic involved in recasting the equations in Physics, and the algorithms in Engineering, in variational terms. The most classical of these ‘magics’ is the Lagrange’s formulation of the Newtonian mechanics. An accessible modern take on all this and more appears in the February 19, 2019 issue of The New Yorker magazine: https://www.newyorker.com/science/elements/a-different-kind-of-theory-of-everything?reload=true <br />
<br />
My talk is concerned with a variational (optimal control type) formulation of the problem of nonlinear filtering/estimation. Such formulations are referred to as duality between optimal estimation and optimal control. The first duality principle appears in the seminal (1961) paper of Kalman-Bucy, where the problem of minimum variance estimation is shown to be dual to a linear quadratic optimal control problem. <br />
<br />
In my talk, I will describe a generalization of the Kalman-Bucy duality theory to nonlinear filtering. The generalization is an exact extension, in the sense that the dual optimal control problem has the same minimum variance structure for linear and nonlinear filtering problems. Kalman-Bucy’s classical result is shown to be a special case. During the talk, I will also attempt to review other types of duality relationships that have appeared over the years for the problem of linear and nonlinear filtering. <br />
<br />
This is joint work with Jin Won Kim and Sean Meyn. The talk is based on the following papers: https://arxiv.org/pdf/1903.11195.pdf and https://arxiv.org/pdf/1904.01710.pdf.</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=18057Applied/ACMS2019-10-01T12:56:23Z<p>Jeanluc: /* Fall 2019 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Sept 6<br />
|[http://math.mit.edu/~lzepeda/ Leonardo Andrés Zepeda Núñez] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Leonardo Andrés Zepeda Núñez (UW-Madison)|Deep Learning for Electronic Structure Computations: A Tale of Symmetries, Locality, and Physics]]''<br />
| Li<br />
|-<br />
| Sept 13<br />
|[http://dfloryan.mycpanel.princeton.edu/ Daniel Floryan] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Daniel Floryan (UW-Madison)|Flexible Inertial Swimmers]]''<br />
| Jean-Luc<br />
|-<br />
| Sept 14-15<br />
|[https://www.ams.org/meetings/sectional/2267_program.html AMS sectional meeting]<br />
| UW-Madison<br />
|-<br />
| Sept 20<br />
|[https://www.gfdl.noaa.gov/mitch-bushuk/ Mitch Bushuk] (GFDL/Princeton)<br />
|''[[Applied/ACMS/absF19#Mitch Bushuk (GFDL/Princeton)|Arctic Sea Ice Predictability in a Changing Cryosphere]]''<br />
| Chen<br />
|-<br />
| Sept 20 (colloquium, 4pm, B239)<br />
|[https://services.math.duke.edu/~jianfeng/ Jianfeng Lu] (Duke)<br />
|''[[Applied/ACMS/absF19#Jianfeng Lu (Duke)|How to "localize" the computation?]]''<br />
| Li<br />
|-<br />
| Sept 27<br />
|[http://www.math.wisc.edu/~qinli/ Qin Li] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Qin Li (UW-Madison)|The power of randomness in scientific computing]]''<br />
| host<br />
|-<br />
| Oct 4<br />
|[https://isearch.asu.edu/profile/2169104 Joel Nishimura] (Arizona State)<br />
|''[[Applied/ACMS/absF19#Joel Nishimura (Arizona State)|Random graph models with fixed degree sequences: choices, consequences and irreducibility proofs for sampling]]''<br />
| Cochran<br />
|-<br />
| Oct 11<br />
|[http://pi.math.cornell.edu/~ajt/ Alex Townsend] (Cornell)<br />
|''[[Applied/ACMS/absF19#Alex Townsend (Cornell)|TBA]]''<br />
| Li<br />
|-<br />
| Oct 18<br />
|[http://mehta.mechse.illinois.edu/ Prashant G. Mehta] (UIUC)<br />
|''[[Applied/ACMS/absF19#Prashant G. Mehta (UIUC)|Title: What is the Lagrangian for Nonlinear Filtering?]]''<br />
| Chen<br />
|-<br />
| Oct 25<br />
|<br />
|''[[Applied/ACMS/absF19# TBA|TBA]]''<br />
| <br />
|-<br />
| Nov 1<br />
|[https://users.oden.utexas.edu/~tanbui/ Tan Bui] (UT-Austin)<br />
|''[[Applied/ACMS/absF19#Tan Bui (UT-Austin)|Title: TBA]]''<br />
| Li<br />
|-<br />
| Nov 8<br />
|[https://pan.labs.wisc.edu/staff/pan-wenxiao/ Wenxiao Pan] (UW)<br />
|''[[Applied/ACMS/absF19#Wenxiao Pan (UW)|TBA]]''<br />
| Spagnolie<br />
| <br />
|-<br />
| Nov 15<br />
|[https://www.math.wisc.edu/~pgera/ Prerna Gera] (UW)<br />
|''[[Applied/ACMS/absF19#Prerna Gera (UW)|TBA]]''<br />
| Spagnolie<br />
|-<br />
| Dec 6<br />
|[https://math.berkeley.edu/~linlin/ Lin Lin] (Berkeley)<br />
|''[[Applied/ACMS/absF19#Lin Lin (UC Berkeley)|TBA]]''<br />
| Li<br />
|-<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
*[[Applied/ACMS/Spring2020|Spring 2020]]<br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluchttps://www.math.wisc.edu/wiki/index.php?title=Applied/Physical_Applied_Math&diff=18056Applied/Physical Applied Math2019-10-01T09:35:39Z<p>Jeanluc: /* Fall 2019 */</p>
<hr />
<div>= Physical Applied Math Group Meeting =<br />
<br />
*'''When:''' Thursdays at 4:00pm (unless there is a departmental meeting)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the Physical Applied Math mailing list:''' See the [https://admin.lists.wisc.edu/index.php?p=11&l=phys_appl_math mailing list website].<br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Sept. 5<br />
|<br />
|Organizational meeting<br />
|-<br />
|Sept. 12<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Sept. 19<br />
|Yu<br />
|Convection-induced singularity suppression in the Keller-Segel and other nonlinear PDEs<br />
|-<br />
|Sept. 26<br />
|Son<br />
|State-constraint static Hamilton-Jacobi equations in nested domains<br />
|-<br />
|Oct. 3<br />
|Hongfei<br />
|Microswimmers interacting with walls<br />
|-<br />
|Oct. 10<br />
|Alex Townsend? Check<br />
|<br />
|-<br />
|Oct. 17<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Oct. 24<br />
|Prerna<br />
|<br />
|-<br />
|Oct. 31<br />
|<br />
|<br />
|-<br />
|Nov. 7<br />
|Bryan<br />
|<br />
|-<br />
|Nov. 11<br />
|<br />
|<br />
|-<br />
|Nov. 14<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Nov. 21<br />
|<br />
|Practice talks for DFD<br />
|-<br />
|Dec. 5<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Dec. 12<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|}<br />
<br />
== Spring 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 24<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Jan. 31<br />
|Jean-Luc<br />
|Organizational meeting; J-LT speaks on Vortices in a channel<br />
|-<br />
|Feb. 7<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 14<br />
|Yu<br />
|Suppression of phase separation by mixing<br />
|-<br />
|Feb. 21<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Feb. 28<br />
|Bryan<br />
|Riffles shuffles and mixing<br />
|-<br />
|Mar. 7<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Mar. 14<br />
|Hongfei<br />
|[https://www.springer.com/us/book/9781441916044 Diffusion across potential barriers]<br />
|-<br />
|Mar. 21<br />
|<br />
|''Spring Break''<br />
|-<br />
|Mar. 28<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Apr. 4<br />
|Ruojun<br />
|Internal diffusion-limited aggregation and rotor-router walks with drift<br />
|-<br />
|Apr. 11<br />
|Jiajia<br />
|[https://doi.org/10.1063/1.1675038 Freed, Wiener Integrals and Models of Stiff Polymer Chains]<br />
|-<br />
|Apr. 18<br />
|Wangping<br />
|Entanglement of frictionless strings<br />
|-<br />
|Apr. 25<br />
|John<br />
|pseudo-Anosov homeomorphisms with large entropy<br />
|-<br />
|May 2<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|May 9<br />
|Saverio<br />
|Internal capillary origami (see [https://journals.aps.org/pra/abstract/10.1103/PhysRevA.44.1182 Seifert et al, Shape transformations of vesicles] and [https://www.annualreviews.org/doi/full/10.1146/annurev-fluid-122316-050130?casa_token=lYj2Hmpn0fEAAAAA:269tjv-n7Odyzgam7PniTi5WmNPjP0qVrO7qxV0a8Ox_Tl4fNsawlxTves-ev7vI_h9Sx_0jKfwK Bico et al., Elastocapillarity (Review article)])<br />
|-<br />
|}<br />
<br />
== Fall 2018 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
|-<br />
|Jan. 31<br />
|Jean-Luc<br />
|Organizational meeting; J-LT speaks on Aldous and Diaconis, [https://www.ams.org/journals/bull/1999-36-04/S0273-0979-99-00796-X/ Longest increasing subsequences: from patience sorting to the Baik-Deift-Johansson theorem]<br />
|-<br />
|Sep. 13<br />
|Son<br />
|[https://arxiv.org/abs/1808.06129 Rate of convergence for periodic homogenization of convex Hamilton-Jacobi equations in one dimension]<br />
|-<br />
|Sep. 20<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Sep. 27<br />
|[https://www.math.cmu.edu/~gautam/sj/index.html Gautam Iyer] (CMU)<br />
|[https://arxiv.org/abs/1806.03699 Dissipation enhancement by mixing]<br />
|-<br />
|Oct. 4<br />
|Gage<br />
|[https://www.dropbox.com/s/tjc4v03cwgzeppm/Group_talk_ab___notes.pdf Escape rates of random walks on free groups]<br />
|-<br />
|Oct. 11<br />
|<i>cancelled</i><br />
|<br />
|-<br />
|Oct. 18<br />
|Yu Feng<br />
|Relaxation enhancement for Advective Cahn-Hilliard (practice for specialty)<br />
|-<br />
|Oct. 25<br />
|Yu's specialty <b>2-3pm, B139</b><br />
|Relaxation enhancement for Advective Cahn-Hilliard<br />
|-<br />
|Nov. 1<br />
|Wil<br />
|Powers, [https://journals.aps.org/rmp/abstract/10.1103/RevModPhys.82.1607; Dynamics of filaments and membranes in a viscous fluid]; Guven et al. [http://iopscience.iop.org/article/10.1088/1751-8113/47/35/355201/pdf Environmental bias and elastic curves on surfaces]<br />
|-<br />
|Nov. 8<br />
|Tom<br />
|[https://arxiv.org/abs/1809.01190 Mixing by jellyfish]<br />
|-<br />
|Nov. 15<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|Nov. 22<br />
|<br />
|''Thanksgiving Break''<br />
|-<br />
|Nov. 29<br />
|Chris<br />
|Sun et al., [https://www.sciencedirect.com/science/article/pii/S0167278911001588 A mathematical model for the synchronization of cows]<br />
|-<br />
|Dec. 6<br />
|<br />
|''Faculty Meeting''<br />
|-<br />
|'''Dec. 12, B239'''<br />
|Jean-Luc<br />
|Cooking food by flipping<br />
|-<br />
|Dec. 13<br />
|<br />
|''Faculty Meeting''<br />
|}<br />
<br />
== Archived semesters ==<br />
*[[Applied/Physical_Applied_Math/Spring2018|Spring 2018]]<br />
*[[Applied/Physical_Applied_Math/Fall2017|Fall 2017]]<br />
*[[Applied/Physical_Applied_Math/Spring2017|Spring 2017]]<br />
*[[Applied/Physical_Applied_Math/Fall2016|Fall 2016]]<br />
*[[Applied/Physical_Applied_Math/Spring2016|Spring 2016]]<br />
*[[Applied/Physical_Applied_Math/Fall2015|Fall 2015]]<br />
*[[Applied/Physical_Applied_Math/Spring2015|Spring 2015]]<br />
*[[Applied/Physical_Applied_Math/Summer2014|Summer 2014]]<br />
*[[Applied/Physical_Applied_Math/Spring2014|Spring 2014]]<br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Jeanluc