Difference between revisions of "Analysis Seminar"

From Math
Jump to: navigation, search
(2017-2018 Analysis Seminar Schedule)
(Analysis Seminar Schedule)
 
(189 intermediate revisions by 9 users not shown)
Line 4: Line 4:
 
The seminar will  meet Tuesdays, 4:00 p.m. in VV B139, unless otherwise indicated.
 
The seminar will  meet Tuesdays, 4:00 p.m. in VV B139, unless otherwise indicated.
  
If you wish to invite a speaker please  contact  Betsy at stovall(at)math
+
If you wish to invite a speaker please  contact  Brian at street(at)math
  
 
===[[Previous Analysis seminars]]===
 
===[[Previous Analysis seminars]]===
  
= 2017-2018 Analysis Seminar Schedule =
+
= Analysis Seminar Schedule =
 
{| cellpadding="8"
 
{| cellpadding="8"
 
!align="left" | date   
 
!align="left" | date   
Line 16: Line 16:
 
!align="left" | host(s)
 
!align="left" | host(s)
 
|-
 
|-
|September 8 in B239
+
|Sept 11
| Tess Anderson
+
| Simon Marshall
 
| UW Madison
 
| UW Madison
|[[#linktoabstract |   A Spherical Maximal Function along the Primes]]
+
|[[#Simon Marshall | Integrals of eigenfunctions on hyperbolic manifolds ]]
|Tonghai
+
|  
 
|-
 
|-
|September 19
+
|'''Wednesday, Sept 12'''
| Brian Street
+
| Gunther Uhlmann 
| UW Madison
+
| University of Washington
|[[#Brian Street  |  Convenient Coordinates ]]
+
| Distinguished Lecture Series
| Betsy
+
| See colloquium website for location
 
|-
 
|-
|September 26
+
|'''Friday, Sept 14'''
| Hiroyoshi Mitake
+
| Gunther Uhlmann 
| Hiroshima University
+
| University of Washington
|[[#Hiroyoshi Mitake  |  Derivation of multi-layered interface system and its application ]]
+
| Distinguished Lecture Series
| Hung
+
| See colloquium website for location
 
|-
 
|-
|October 3
+
|Sept 18
| Joris Roos
+
| Grad Student Seminar
| UW Madison
+
|  
|[[#Joris Roos  |  A polynomial Roth theorem on the real line ]]
+
|
| Betsy
+
|
 
|-
 
|-
|October 10
+
|Sept 25
| Michael Greenblatt
+
| Grad Student Seminar
| UI Chicago
+
|
|[[#Michael Greenblatt  |  Maximal averages and Radon transforms for two-dimensional hypersurfaces ]]
+
|
| Andreas
+
|
 
|-
 
|-
|October 17
+
|Oct 9
| David Beltran
+
| Hong Wang
| Basque Center of Applied Mathematics
+
| MIT
|[[#David Beltran Fefferman-Stein inequalities ]]
+
|[[#Hong Wang About Falconer distance problem in the plane ]]
| Andreas
+
| Ruixiang
 
|-
 
|-
|Wednesday, October 18, 4:00 p.m.  in B131
+
|Oct 16
|Jonathan Hickman
+
| Polona Durcik
|University of Chicago
+
| Caltech
|[[#Jonathan Hickman | Factorising X^n ]]
+
|[[#Polona Durcik |   Singular Brascamp-Lieb inequalities and extended boxes in R^n ]]
|Andreas
+
| Joris
 
|-
 
|-
|October 24
+
|Oct 23
| Xiaochun Li
+
| Song-Ying Li
| UIUC
+
| UC Irvine
|[[#Xiaochun Li  |  Recent progress on the pointwise convergence problems of Schroedinger equations ]]
+
|[[#Song-Ying Li  |  Estimates for the first positive eigenvalue of Kohn Laplacian on a pseudo-Hermitian manifold ]]
| Betsy
+
| Xianghong
 
|-
 
|-
|Thursday, October 26, 4:30 p.m. in B139
+
|Oct 30
| Fedor Nazarov
+
|Grad student seminar
| Kent State University
+
|
|[[#Fedor Nazarov  |  The Lerner-Ombrosi-Perez bound in the Muckenhoupt Wheeden conjecture is sharp  ]]
+
|
| Sergey, Andreas
+
|
|-
 
|Friday, October 27, 4:00 p.m.  in B239
 
| Stefanie Petermichl
 
| University of Toulouse
 
|[[#Stefanie Petermichl  | Higher order Journé commutators  ]]
 
| Betsy, Andreas
 
|-
 
|Wednesday, November 1, 4:00 p.m. in B239 (Colloquium)
 
| Shaoming Guo
 
| Indiana University
 
|[[#Shaoming Guo  |  Parsell-Vinogradov systems in higher dimensions ]]
 
| Andreas
 
 
|-
 
|-
|November 14
+
|Nov 6
| Naser Talebizadeh Sardari
+
| Hanlong Fang
 
| UW Madison
 
| UW Madison
|[[#Naser Talebizadeh Sardari Quadratic forms and the semiclassical eigenfunction hypothesis ]]
+
|[[#Hanlong Fang A generalization of the theorem of Weil and Kodaira on prescribing residues ]]
| Betsy
+
| Brian
 
|-
 
|-
|November 28
+
||'''Monday, Nov. 12, B139'''
| Xianghong Chen
+
| Kyle Hambrook
| UW Milwaukee
+
| San Jose State University
|[[#Xianghong Chen  |  Some transfer operators on the circle with trigonometric weights ]]
+
|[[#Kyle Hambrook Fourier Decay and Fourier Restriction for Fractal Measures on Curves ]]
| Betsy
 
|-
 
|Monday, December 4, 4:00, B139
 
| Bartosz Langowski and Tomasz Szarek
 
| Institute of Mathematics, Polish Academy of Sciences
 
|[[#Bartosz Langowski and Tomasz Szarek Discrete Harmonic Analysis in the Non-Commutative Setting ]]
 
| Betsy
 
|-
 
|December 12
 
| Alex Stokolos
 
| GA Southern
 
|[[#linktoabstract  |  Title ]]
 
 
| Andreas
 
| Andreas
 
|-
 
|-
|Wednesday, December 13, 4:00, B239 (Colloquium)
+
|Nov 13
|Bobby Wilson (MIT)
+
| Laurent Stolovitch
|[[#Bobby Wilson | Projections in Banach Spaces and Harmonic Analysis ]]
+
| Université de Nice - Sophia Antipolis
| Andreas
+
|[[#Laurent Stolovitch  |   Equivalence of Cauchy-Riemann manifolds and multisummability theory ]]
 +
|Xianghong
 
|-
 
|-
|January 30
+
|Nov 20
 +
| Grad Student Seminar
 
|  
 
|  
 +
|[[#linktoabstract  |    ]]
 
|  
 
|  
| [[#linkofabstract | Title]]
 
|
 
 
|-
 
|-
|February 6
+
|Nov 27
| Dong Dong
+
| No Seminar
| UIUC
 
| [[#Dong Dong | Hibert transforms in a 3 by 3 matrix and applications in number theory]]
 
|Betsy
 
|-
 
|February 13
 
 
|  
 
|  
 +
|[[#linktoabstract  |    ]]
 
|  
 
|  
| [[#linkofabstract | Title]]
 
|
 
 
|-
 
|-
|February 20
+
|Dec 4
 +
| No Seminar
 +
|[[#linktoabstract  |    ]]
 
|  
 
|  
 +
|-
 +
|Jan 22
 +
| Brian Cook
 +
| Kent
 +
|[[#Brian Cook  |  Equidistribution results for integral points on affine homogenous algebraic varieties ]]
 +
| Street
 +
|-
 +
|Jan 29
 +
| No Seminar
 
|  
 
|  
| [[#linkofabstract | Title]]
+
|[[#linktoabstract  |   ]]
 
|
 
|
 
|-
 
|-
|February 27
+
|Feb 5, '''B239'''
 +
| Alexei Poltoratski
 +
| Texas A&M
 +
|[[#Alexei Poltoratski  |  Completeness of exponentials: Beurling-Malliavin and type problems ]]
 +
| Denisov
 +
|-
 +
|'''Friday, Feb 8'''
 +
| Aaron Naber
 +
| Northwestern University
 +
|[[#linktoabstract  |  A structure theory for spaces with lower Ricci curvature bounds ]]
 +
| See colloquium website for location
 +
|-
 +
|Feb 12
 +
| Shaoming Guo
 +
| UW Madison
 +
|[[#Shaoming Guo | Polynomial Roth theorems in Salem sets  ]]
 
|  
 
|  
|  
+
|-
| [[#linkofabstract | Title]]
+
|'''Wed, Feb 13, B239'''
 +
| Dean Baskin
 +
| TAMU
 +
|[[# Dean Baskin  |  Radiation fields for wave  equations ]]
 +
|  Colloquium
 +
|-
 +
|'''Friday, Feb 15'''
 +
| Lillian Pierce
 +
| Duke
 +
|[[#Lillian Pierce  |  Short character sums ]]
 +
|  Colloquium
 +
|-
 +
|'''Monday,  Feb 18, 3:30 p.m, B239.'''
 +
| Daniel Tataru
 +
| UC Berkeley
 +
|[[#Daniel Tataru  |   A Morawetz inequality for water waves ]]
 +
|  PDE Seminar
 +
|-
 +
|Feb 19
 +
| Wenjia Jing
 +
|Tsinghua University
 +
|Periodic  homogenization of Dirichlet problems in perforated domains: a unified proof
 +
| PDE Seminar
 +
|-
 +
|Feb 26
 +
| No Seminar
 +
|
 
|
 
|
 
|-
 
|-
|Wednesday, March 7, 4:00 p.m.
+
|Mar 5
| Winfried Sickel
+
| Loredana Lanzani
|Friedrich-Schiller-Universität Jena
+
| Syracuse University
| [[#linkofabstract | Title]]
+
|[[#Loredana Lanzani  |   On regularity and irregularity of the Cauchy-Szegő projection in several complex variables ]]
|Andreas
+
| Xianghong
 
|-
 
|-
|March 13
+
|Mar 12
|  
+
| Trevor Leslie
|  
+
| UW Madison
| [[#linkofabstract | Title]]
+
|[[#Trevor Leslie  |   Energy Equality for the Navier-Stokes Equations at the First Possible Blowup Time ]]
 
|
 
|
 
|-
 
|-
|March 20
+
|Mar 19
 +
|Spring Break!
 
|  
 
|  
|  
+
|
| [[#linkofabstract | Title]]
 
 
|
 
|
 
|-
 
|-
|April 3
+
|Mar 26
 +
| No seminar
 
|  
 
|  
 +
|[[#linktoabstract  |    ]]
 
|  
 
|  
| [[#linkofabstract | Title]]
 
|
 
 
|-
 
|-
|April 10
+
|Apr 2
|  
+
| Stefan Steinerberger
|  
+
| Yale
| [[#linkofabstract | Title]]
+
|[[#Stefan Steinerberger  |   Wasserstein Distance as a Tool in Analysis ]]
|
+
| Shaoming, Andreas
 +
|-
 +
 
 +
|Apr 9
 +
| Franc Forstnerič
 +
| Unversity of Ljubljana
 +
|[[#Franc Forstnerič  |  Minimal surfaces by way of complex analysis ]]
 +
| Xianghong, Andreas
 
|-
 
|-
|April 17
+
|Apr 16
|  
+
| Andrew Zimmer
|  
+
| Louisiana State University
| [[#linkofabstract | Title]]
+
|[[#Andrew Zimmer  |   The geometry of domains with negatively pinched Kaehler metrics ]]
|
+
| Xianghong
 
|-
 
|-
|April 24
+
|Apr 23
 +
| Reserved
 
|  
 
|  
|
+
|[[#linktoabstract  |   Title ]]
| [[#linkofabstract | Title]]
+
| Street
|
 
 
|-
 
|-
|May 1
+
|Apr 30
|  
+
| Zhen Zeng
|  
+
| UPenn
| [[#linkofabstract | Title]]
+
|[[#linktoabstract  |   Title ]]
|
+
| Shaoming
 
|-
 
|-
 
|}
 
|}
  
 
=Abstracts=
 
=Abstracts=
===Brian Street===
+
===Simon Marshall===
 +
 
 +
''Integrals of eigenfunctions on hyperbolic manifolds''
 +
 
 +
Let X be a compact hyperbolic manifold, and let Y be a totally geodesic closed submanifold in X.  I will discuss the problem of bounding the integral of a Laplace eigenfunction on X over Y, as the eigenvalue tends to infinity.  I will present an upper bound for these integrals that is sharp on average, and briefly describe ongoing work with Farrell Brumley in which we attempt to produce eigenfunctions with very large periods.
 +
 
 +
 
 +
===Hong Wang===
 +
 
 +
''About Falconer distance problem in the plane''
 +
 
 +
If E is a compact set of Hausdorff dimension greater than 5/4 on the plane, we prove that there is a point x\in E such that the set of distances between x and E has positive Lebesgue measure. Our result improves upon Wolff's theorem for dim E> 4/3. This is joint work with Larry Guth, Alex Iosevich and Yumeng Ou.
 +
 
 +
===Polona Durcik===
 +
 
 +
''Singular Brascamp-Lieb inequalities and extended boxes in R^n''
 +
 
 +
Brascamp-Lieb inequalities are L^p estimates for certain multilinear forms on functions on Euclidean spaces. In this talk we consider singular Brascamp-Lieb inequalities, which arise when one of the functions is replaced by a Calderon-Zygmund kernel. We focus on a family of multilinear forms in R^n with a certain cubical structure and discuss their connection to some patterns in positive density subsets in R^n. Based on joint works with V. Kovac and C. Thiele.
 +
 
 +
 
 +
===Song-Ying Li===
 +
 
 +
''Estimates for the first positive eigenvalue of Kohn Laplacian on a pseudo-Hermitian manifold''
 +
 
 +
In this talk, I will present my recent works with my collaborators on the lower bound and upper bounds estimates
 +
for the first positive eigenvalues of Kohn Laplacian and sub-Laplacian on a strictly pseudoconvex pseudo-Hermitian CR manifold,
 +
which include CR Lichnerowicz-Obata theorem for the lower and upper bounds for the first positive eigenvalue for the
 +
Kohn Laplacian on strictly pseudoconvex hypersurfaces.
 +
 
 +
 
 +
===Hanlong Fan===
 +
 
 +
''A generalization of the theorem of Weil and Kodaira on prescribing residues''
 +
 
 +
An old theorem of Weil and Kodaira says that: For a K\"ahler manifold X, there exists a closed meromorphic one-form with residue divisor D if and only if D is homologous to zero. In this talk, I will generalize Weil and Kodaira's criterion to non-K\"ahler manifolds.
 +
 
 +
===Kyle Hambrook===
 +
 
 +
''Fourier Decay and Fourier Restriction for Fractal Measures on Curves''
 +
 
 +
I will discuss my recent work on some problems concerning
 +
Fourier decay and Fourier restriction for fractal measures on curves.
 +
 
 +
===Laurent Stolovitch===
 +
 
 +
''Equivalence of Cauchy-Riemann manifolds and multisummability theory''
  
Title: Convenient Coordinates
+
We apply the multisummability theory from Dynamical Systems to CR-geometry. As the main result, we show that two real-analytic hypersurfaces in $\mathbb C^2$ are formally equivalent, if and only if they are $C^\infty$ CR-equivalent at the respective point. As a corollary, we prove that all formal equivalences between real-algebraic Levi-nonflat hypersurfaces in $\mathbb C^2$ are algebraic (and in particular convergent). This is a joint work with I. Kossovskiy and B. Lamel.
  
Abstract:  We discuss the method of picking a convenient coordinate system adapted to vector fields.  Let X_1,...,X_q be either real or complex C^1 vector fields.  We discuss the question of when there is a coordinate system in which the vector fields are smoother (e.g., C^m, or C^\infty, or real analytic).  By answering this in a quantitative way, we obtain coordinate charts which can be used as generalized scaling maps.  When the vector fields are real this is joint work with Stovall, and continues in the line of quantitative sub-Riemannian geometry initiated by Nagel, Stein, and Wainger.  When the vector fields are complex one obtains a geometry with more structure which can be thought of as "sub-Hermitian".
 
  
===Hiroyoshi Mitake===
+
===Brian Cook===
  
Title:  Derivation of multi-layered interface system and its application
+
''Equidistribution results for integral points on affine homogenous algebraic varieties''
  
Abstract:  In this talk, I will propose a multi-layered interface system which can
+
Let Q be a homogenous integral polynomial of degree at least two. We consider certain results and questions concerning the distribution of the integral points on the level sets of Q.
be formally derived by the singular limit of the weakly coupled system of  
 
the Allen-Cahn equation.  By using the level set approach, this system can be
 
written as a quasi-monotone degenerate parabolic system.  
 
We give results of the well-posedness of viscosity solutions, and study the  
 
singularity of each layers. This is a joint work with H. Ninomiya, K. Todoroki.
 
  
===Joris Roos===
+
===Alexei Poltoratski===
  
Title: A polynomial Roth theorem on the real line
+
''Completeness of exponentials: Beurling-Malliavin and type problems''
  
Abstract: For a polynomial P of degree greater than one, we show the existence of patterns of the form (x,x+t,x+P(t)) with a gap estimate on t in positive density subsets of the reals. This is an extension of an earlier result of Bourgain. Our proof is a combination of Bourgain’s approach and more recent methods that were originally developed for the study of the bilinear Hilbert transform along curves. This talk is based on a joint work with Polona Durcik and Shaoming Guo.
+
This talk is devoted to two old problems of harmonic analysis mentioned in the title. Both problems ask when a family of complex exponentials is complete (spans) an L^2-space. The Beruling-Malliavin problem was solved in the early 1960s and I will present its classical solution along with modern generalizations and applications. I will then discuss history and recent progress in the type problem, which stood open for more than 70 years.
  
===Michael Greenblatt===
 
  
Title:  Maximal averages and Radon transforms for two-dimensional hypersurfaces
+
===Shaoming Guo===
  
Abstract:  A general local result concerning L^p boundedness of maximal averages over 2D hypersurfaces is described, where p > 2. The surfaces are allowed to have either the traditional smooth density function or a singularity growing as |(x,y)|^{-t} for some 0 < t < 2. This result is a generalization of a theorem of Ikromov, Kempe, and Mueller. Similar methods can be used to show sharp L^p to L^p_a Sobolev estimates for associated Radon transform operators when p is in a certain interval containing 2.
+
''Polynomial Roth theorems in Salem sets''
  
===David Beltran===
+
Let P(t) be a polynomial of one real variable. I will report a result on searching for patterns of the form (x, x+t, x+P(t)) within Salem sets, whose Hausdorff dimension is sufficiently close to one. Joint work with Fraser and Pramanik.
  
Title:  Fefferman Stein Inequalities
 
  
Abstract:  Given an operator T, we focus on obtaining two-weighted inequalities in which the weights are related via certain maximal function. These inequalites, which originated in work of Fefferman and Stein, have been established in an optimal way for different classical operators in Harmonic Analysis. In this talk, we survey some classical results and we present some recent Fefferman-Stein inequalities for pseudodifferential operators and for the solution operators to dispersive equations.
 
  
===Jonathan Hickman===
 
  
Title: Factorising X^n.
+
===Dean Baskin===
  
Question: how many ways can the polynomial $X^n$ be factorised as a product of linear factors? Answer: it depends on the ring... In this talk I will describe joint work with Jim Wright investigating certain exponential sum estimates over rings of integers modulo N. This theory serves as a discrete analogue of the (euclidean) Fourier restriction problem, a central question in contemporary harmonic analysis. In particular, as part of this study, the question of counting the number of factorisations of polynomials over such rings naturally arises. I will describe how these number-theoretic considerations can themselves be approached via methods from harmonic analysis.
+
''Radiation fields for wave equations''
  
===Xiaochun Li ===
+
Radiation fields are rescaled limits of solutions of wave equations near "null infinity" and capture the radiation pattern seen by a distant observer. They are intimately connected with the Fourier and Radon transforms and with scattering theory. In this talk, I will define and discuss radiation fields in a few contexts, with an emphasis on spacetimes that look flat near infinity. The main result is a connection between the asymptotic behavior of the radiation field and a family of quantum objects on an associated asymptotically hyperbolic space.
  
Title:  Recent progress on the pointwise convergence problems of Schrodinger equations
+
===Lillian Pierce===
  
Abstract:  Recently, Guth, Du and I solved the pointwise convergence problem of Schrodinger equations in two-dimensional case. We proved that the solution to free Schrodinger equation in R^2 converges to its initial data, provided the initial data belongs to H^s for s larger than 1/3.  This result is sharp, up to the end point, due to Bourgain's example. The proof relies on the polynomial partitioning method and  the decoupling method. In addition, the pointwise convergence problem is closely related to Fourier restriction conjecture.
+
''Short character sums''
  
===Fedor Nazarov=== 
+
A surprisingly diverse array of problems in analytic number theory have at their heart a problem of bounding (from above) an exponential sum, or its multiplicative cousin, a so-called character sum. For example, both understanding the Riemann zeta function or Dirichlet L-functions inside the critical strip, and also counting solutions to Diophantine equations via the circle method or power sieve methods, involve bounding such sums. In general, the sums of interest fall into one of two main regimes: complete sums or incomplete sums, with this latter regime including in particular “short sums.” Short sums are particularly useful, and particularly resistant to almost all known methods. In this talk, we will see what makes a sum “short,” sketch why it would be incredibly powerful to understand short sums, and discuss a curious proof from the 1950’s which is still the best way we know to bound short sums. We will end by describing new work which extends the ideas of this curious proof to bound short sums in much more general situations.
  
Title: The Lerner-Ombrosi-Perez bound in the Muckenhoupt-Wheeden
+
===Loredana Lanzani===
conjecture is sharp.
 
  
Abstract: We show that the upper bound $[w]_{A_1}\log (e+[w]_{A_1})$ for
+
''On regularity and irregularity of the Cauchy-Szegő projection in several complex variables''
the norm of the Hilbert transform on the line as an operator from $L^1(w)$
 
to $L^{1,\infty}(w)$ cannot be improved in general. This is a joint work
 
with Andrei Lerner and Sheldy Ombrosi.
 
  
 +
This talk is a survey of my latest, and now final, collaboration with Eli Stein.
  
===Stefanie Petermichl===
+
It is known that for bounded domains $D$ in $\mathbb C^n$ that are of class $C^2$ and are strongly pseudo-convex, the Cauchy-Szegő projection is bounded in $L^p(\text{b}D, d\Sigma)$ for $1<p<\infty$. (Here $d\Sigma$ is induced Lebesgue measure.)  We show, using appropriate worm domains, that this fails for any $p\neq 2$, when we assume that the domain in question is only weakly pseudo-convex. Our starting point are the ideas of Kiselman-Barrett introduced more than 30 years ago in the analysis of the Bergman projection. However the study of the Cauchy-Szegő projection raises a number of new issues and obstacles that need to be overcome. We will also compare these results to the analogous problem for the Cauchy-Leray integral, where however the relevant counter-example is of much simpler nature.
Title: Higher order Journé commutators
 
  
Abstract: We consider questions that stem from operator theory via Hankel and
+
===Trevor Leslie===
Toeplitz forms and target (weak) factorisation of Hardy spaces. In
 
more basic terms, let us consider a function on the unit circle in its
 
Fourier representation. Let P_+ denote the projection onto
 
non-negative and P_- onto negative frequencies. Let b denote
 
multiplication by the symbol function b. It is a classical theorem by
 
Nehari that the composed operator P_+ b P_- is bounded on L^2 if and
 
only if b is in an appropriate space of functions of bounded mean
 
oscillation. The necessity makes use of a classical factorisation
 
theorem of complex function theory on the disk. This type of question
 
can be reformulated in terms of commutators [b,H]=bH-Hb with the
 
Hilbert transform H=P_+ - P_- . Whenever factorisation is absent, such
 
as in the real variable setting, in the multi-parameter setting or
 
other, these classifications can be very difficult.
 
  
Such lines were begun by Coifman, Rochberg, Weiss (real variables) and
+
''Energy Equality for the Navier-Stokes Equations at the First Possible Blowup Time''
by Cotlar, Ferguson, Sadosky (multi-parameter) of characterisation of
 
spaces of bounded mean oscillation via L^p boundedness of commutators.
 
We present here an endpoint to this theory, bringing all such
 
characterisation results under one roof.
 
  
The tools used go deep into modern advances in dyadic harmonic
+
In this talk, we discuss the problem of energy equality for strong solutions of the Navier-Stokes Equations (NSE) at the first time where such solutions may lose regularity.  Our approach is motivated by a famous theorem of Caffarelli, Kohn, and Nirenberg, which states that the set of singular points associated to a suitable weak solution of the NSE has parabolic Hausdorff dimension of at most 1.  In particular, we furnish sufficient conditions for energy equality which depend on the dimension of the singularity set in addition to time and space integrability assumptions; in doing so we improve upon the classical results when attention is restricted to the first blowup time.  When our method is inconclusive, we are able to quantify the possible failure of energy equality in terms of the lower local dimension and the ''concentration dimension'' of a certain measure associated to the solution.  The work described is joint with Roman Shvydkoy (UIC).
analysis, while preserving the Ansatz from classical operator theory.
 
  
===Shaoming Guo ===
+
===Stefan Steinerberger===
Title: Parsell-Vinogradov systems in higher dimensions
 
  
Abstract:
+
''Wasserstein Distance as a Tool in Analysis''
I will present a few results on counting the numbers of integer solutions of Parsell-Vinogradov systems in higher dimensions.
 
Applications to Waring’s problem and to the problem of counting rational linear subspaces lying on certain hyper-surface will be discussed.
 
Joint works with Jean Bourgain, Ciprian Demeter and Ruixiang Zhang.
 
  
===Naser Talebizadeh Sardari===
+
Wasserstein Distance is a way of measuring the distance between two probability distributions (minimizing it is a main problem in Optimal Transport). We will give a gentle Introduction into what it means and then use it to prove (1) a completely elementary but possibly new and quite curious inequality for real-valued functions and (2) a statement along the following lines: linear combinations of eigenfunctions of elliptic operators corresponding to high frequencies oscillate a lot and vanish on a large set of co-dimension 1 (this is already interesting for trigonometric polynomials on the 2-torus, sums of finitely many sines and cosines, whose sum has to vanish on long lines) and (3) some statements in Basic Analytic Number Theory that drop out for free as a byproduct.
  
Title: Quadratic forms and the semiclassical eigenfunction hypothesis
+
===Franc Forstnerič===
  
Abstract:  Let <math>Q(X)</math> be any integral primitive positive definite quadratic form in <math>k</math> variables, where <math>k\geq4</math>,  and discriminant <math>D</math>. For any integer <math>n</math>, we give an upper bound on the number of integral solutions of <math>Q(X)=n</math>  in terms of <math>n</math>, <math>k</math>, and <math>D</math>. As a corollary, we prove  a conjecture of Lester and Rudnick on the small scale equidistribution of almost all functions belonging to any orthonormal basis of a given  eigenspace of the Laplacian on the flat torus <math>\mathbb{T}^d</math> for <math>d\geq 5</math>. This conjecture is motivated by the work of Berry\cite{Berry, Michael} on semiclassical eigenfunction hypothesis.
+
''Minimal surfaces by way of complex analysis''
  
===Xianghong Chen===
+
After a brief historical introduction, I will present some recent developments in the theory of minimal surfaces in Euclidean spaces which have been obtained by complex analytic methods. The emphasis will be on results pertaining to the global theory of minimal surfaces including Runge and Mergelyan approximation, the conformal Calabi-Yau problem, properly immersed and embedded minimal surfaces, and a new result on the Gauss map of minimal surfaces.
  
Title:  Some transfer operators on the circle with trigonometric weights
+
===Andrew Zimmer===
  
Abstract:  A transfer operator is an averaging operator over the preimages of a given map. Certain dynamical properties of the map can be studied through its associated transfer operator. In this talk we will introduce a class of weighted transfer operators associated to the Bernoulli maps on the circle (i.e. multiplication by a given integer, mod 1). We will illustrate how the spectral properties of these operators may depend on the specific weight chosen and demonstrate multiple phase transitions. We also present some results on evaluating the spectral radii and corresponding eigenfunctions of these operators, as well as their connections to Fourier analysis. This is joint work with Hans Volkmer.
+
''The geometry of domains with negatively pinched Kaehler metrics''
  
===Dong Dong===
+
Every bounded pseudoconvex domain in C^n has a natural complete metric: the Kaehler-Einstein metric constructed by Cheng-Yau. When the boundary of the domain is strongly pseudoconvex, Cheng-Yau showed that the holomorphic sectional curvature of this metric is asymptotically a negative constant. In this talk I will describe some partial converses to this result, including the following: if a smoothly bounded convex domain has a complete Kaehler metric with close to constant negative holomorphic sectional curvature near the boundary, then the domain is strongly pseudoconvex. This is joint work with F. Bracci and H. Gaussier.
  
Title: Hibert transforms in a 3 by 3 matrix and applications in number theory
 
  
Abstract:  This talk could interest both analysts and number theorists. I will first present 35 variants of Hilbert transforms, with a focus on their connections with ergodic theory, number theory, and combinatorics. Then I will show how to use Fourier analysis tools to reduce a number theory problem (Roth theorem) to an algebraic geometry problem: this joint work Li and Sawin fully answers a question of Bourgain and Chang about three-term polynomial progressions in subsets of finite fields. I guarantee that a second-year graduate student can understand at least 50% of the talk.
 
  
 
=Extras=
 
=Extras=
 
[[Blank Analysis Seminar Template]]
 
[[Blank Analysis Seminar Template]]

Latest revision as of 18:52, 15 April 2019

Analysis Seminar

The seminar will meet Tuesdays, 4:00 p.m. in VV B139, unless otherwise indicated.

If you wish to invite a speaker please contact Brian at street(at)math

Previous Analysis seminars

Analysis Seminar Schedule

date speaker institution title host(s)
Sept 11 Simon Marshall UW Madison Integrals of eigenfunctions on hyperbolic manifolds
Wednesday, Sept 12 Gunther Uhlmann University of Washington Distinguished Lecture Series See colloquium website for location
Friday, Sept 14 Gunther Uhlmann University of Washington Distinguished Lecture Series See colloquium website for location
Sept 18 Grad Student Seminar
Sept 25 Grad Student Seminar
Oct 9 Hong Wang MIT About Falconer distance problem in the plane Ruixiang
Oct 16 Polona Durcik Caltech Singular Brascamp-Lieb inequalities and extended boxes in R^n Joris
Oct 23 Song-Ying Li UC Irvine Estimates for the first positive eigenvalue of Kohn Laplacian on a pseudo-Hermitian manifold Xianghong
Oct 30 Grad student seminar
Nov 6 Hanlong Fang UW Madison A generalization of the theorem of Weil and Kodaira on prescribing residues Brian
Monday, Nov. 12, B139 Kyle Hambrook San Jose State University Fourier Decay and Fourier Restriction for Fractal Measures on Curves Andreas
Nov 13 Laurent Stolovitch Université de Nice - Sophia Antipolis Equivalence of Cauchy-Riemann manifolds and multisummability theory Xianghong
Nov 20 Grad Student Seminar
Nov 27 No Seminar
Dec 4 No Seminar
Jan 22 Brian Cook Kent Equidistribution results for integral points on affine homogenous algebraic varieties Street
Jan 29 No Seminar
Feb 5, B239 Alexei Poltoratski Texas A&M Completeness of exponentials: Beurling-Malliavin and type problems Denisov
Friday, Feb 8 Aaron Naber Northwestern University A structure theory for spaces with lower Ricci curvature bounds See colloquium website for location
Feb 12 Shaoming Guo UW Madison Polynomial Roth theorems in Salem sets
Wed, Feb 13, B239 Dean Baskin TAMU Radiation fields for wave equations Colloquium
Friday, Feb 15 Lillian Pierce Duke Short character sums Colloquium
Monday, Feb 18, 3:30 p.m, B239. Daniel Tataru UC Berkeley A Morawetz inequality for water waves PDE Seminar
Feb 19 Wenjia Jing Tsinghua University Periodic homogenization of Dirichlet problems in perforated domains: a unified proof PDE Seminar
Feb 26 No Seminar
Mar 5 Loredana Lanzani Syracuse University On regularity and irregularity of the Cauchy-Szegő projection in several complex variables Xianghong
Mar 12 Trevor Leslie UW Madison Energy Equality for the Navier-Stokes Equations at the First Possible Blowup Time
Mar 19 Spring Break!
Mar 26 No seminar
Apr 2 Stefan Steinerberger Yale Wasserstein Distance as a Tool in Analysis Shaoming, Andreas
Apr 9 Franc Forstnerič Unversity of Ljubljana Minimal surfaces by way of complex analysis Xianghong, Andreas
Apr 16 Andrew Zimmer Louisiana State University The geometry of domains with negatively pinched Kaehler metrics Xianghong
Apr 23 Reserved Title Street
Apr 30 Zhen Zeng UPenn Title Shaoming

Abstracts

Simon Marshall

Integrals of eigenfunctions on hyperbolic manifolds

Let X be a compact hyperbolic manifold, and let Y be a totally geodesic closed submanifold in X. I will discuss the problem of bounding the integral of a Laplace eigenfunction on X over Y, as the eigenvalue tends to infinity. I will present an upper bound for these integrals that is sharp on average, and briefly describe ongoing work with Farrell Brumley in which we attempt to produce eigenfunctions with very large periods.


Hong Wang

About Falconer distance problem in the plane

If E is a compact set of Hausdorff dimension greater than 5/4 on the plane, we prove that there is a point x\in E such that the set of distances between x and E has positive Lebesgue measure. Our result improves upon Wolff's theorem for dim E> 4/3. This is joint work with Larry Guth, Alex Iosevich and Yumeng Ou.

Polona Durcik

Singular Brascamp-Lieb inequalities and extended boxes in R^n

Brascamp-Lieb inequalities are L^p estimates for certain multilinear forms on functions on Euclidean spaces. In this talk we consider singular Brascamp-Lieb inequalities, which arise when one of the functions is replaced by a Calderon-Zygmund kernel. We focus on a family of multilinear forms in R^n with a certain cubical structure and discuss their connection to some patterns in positive density subsets in R^n. Based on joint works with V. Kovac and C. Thiele.


Song-Ying Li

Estimates for the first positive eigenvalue of Kohn Laplacian on a pseudo-Hermitian manifold

In this talk, I will present my recent works with my collaborators on the lower bound and upper bounds estimates for the first positive eigenvalues of Kohn Laplacian and sub-Laplacian on a strictly pseudoconvex pseudo-Hermitian CR manifold, which include CR Lichnerowicz-Obata theorem for the lower and upper bounds for the first positive eigenvalue for the Kohn Laplacian on strictly pseudoconvex hypersurfaces.


Hanlong Fan

A generalization of the theorem of Weil and Kodaira on prescribing residues

An old theorem of Weil and Kodaira says that: For a K\"ahler manifold X, there exists a closed meromorphic one-form with residue divisor D if and only if D is homologous to zero. In this talk, I will generalize Weil and Kodaira's criterion to non-K\"ahler manifolds.

Kyle Hambrook

Fourier Decay and Fourier Restriction for Fractal Measures on Curves

I will discuss my recent work on some problems concerning Fourier decay and Fourier restriction for fractal measures on curves.

Laurent Stolovitch

Equivalence of Cauchy-Riemann manifolds and multisummability theory

We apply the multisummability theory from Dynamical Systems to CR-geometry. As the main result, we show that two real-analytic hypersurfaces in $\mathbb C^2$ are formally equivalent, if and only if they are $C^\infty$ CR-equivalent at the respective point. As a corollary, we prove that all formal equivalences between real-algebraic Levi-nonflat hypersurfaces in $\mathbb C^2$ are algebraic (and in particular convergent). This is a joint work with I. Kossovskiy and B. Lamel.


Brian Cook

Equidistribution results for integral points on affine homogenous algebraic varieties

Let Q be a homogenous integral polynomial of degree at least two. We consider certain results and questions concerning the distribution of the integral points on the level sets of Q.

Alexei Poltoratski

Completeness of exponentials: Beurling-Malliavin and type problems

This talk is devoted to two old problems of harmonic analysis mentioned in the title. Both problems ask when a family of complex exponentials is complete (spans) an L^2-space. The Beruling-Malliavin problem was solved in the early 1960s and I will present its classical solution along with modern generalizations and applications. I will then discuss history and recent progress in the type problem, which stood open for more than 70 years.


Shaoming Guo

Polynomial Roth theorems in Salem sets

Let P(t) be a polynomial of one real variable. I will report a result on searching for patterns of the form (x, x+t, x+P(t)) within Salem sets, whose Hausdorff dimension is sufficiently close to one. Joint work with Fraser and Pramanik.



Dean Baskin

Radiation fields for wave equations

Radiation fields are rescaled limits of solutions of wave equations near "null infinity" and capture the radiation pattern seen by a distant observer. They are intimately connected with the Fourier and Radon transforms and with scattering theory. In this talk, I will define and discuss radiation fields in a few contexts, with an emphasis on spacetimes that look flat near infinity. The main result is a connection between the asymptotic behavior of the radiation field and a family of quantum objects on an associated asymptotically hyperbolic space.

Lillian Pierce

Short character sums

A surprisingly diverse array of problems in analytic number theory have at their heart a problem of bounding (from above) an exponential sum, or its multiplicative cousin, a so-called character sum. For example, both understanding the Riemann zeta function or Dirichlet L-functions inside the critical strip, and also counting solutions to Diophantine equations via the circle method or power sieve methods, involve bounding such sums. In general, the sums of interest fall into one of two main regimes: complete sums or incomplete sums, with this latter regime including in particular “short sums.” Short sums are particularly useful, and particularly resistant to almost all known methods. In this talk, we will see what makes a sum “short,” sketch why it would be incredibly powerful to understand short sums, and discuss a curious proof from the 1950’s which is still the best way we know to bound short sums. We will end by describing new work which extends the ideas of this curious proof to bound short sums in much more general situations.

Loredana Lanzani

On regularity and irregularity of the Cauchy-Szegő projection in several complex variables

This talk is a survey of my latest, and now final, collaboration with Eli Stein.

It is known that for bounded domains $D$ in $\mathbb C^n$ that are of class $C^2$ and are strongly pseudo-convex, the Cauchy-Szegő projection is bounded in $L^p(\text{b}D, d\Sigma)$ for $1<p<\infty$. (Here $d\Sigma$ is induced Lebesgue measure.) We show, using appropriate worm domains, that this fails for any $p\neq 2$, when we assume that the domain in question is only weakly pseudo-convex. Our starting point are the ideas of Kiselman-Barrett introduced more than 30 years ago in the analysis of the Bergman projection. However the study of the Cauchy-Szegő projection raises a number of new issues and obstacles that need to be overcome. We will also compare these results to the analogous problem for the Cauchy-Leray integral, where however the relevant counter-example is of much simpler nature.

Trevor Leslie

Energy Equality for the Navier-Stokes Equations at the First Possible Blowup Time

In this talk, we discuss the problem of energy equality for strong solutions of the Navier-Stokes Equations (NSE) at the first time where such solutions may lose regularity. Our approach is motivated by a famous theorem of Caffarelli, Kohn, and Nirenberg, which states that the set of singular points associated to a suitable weak solution of the NSE has parabolic Hausdorff dimension of at most 1. In particular, we furnish sufficient conditions for energy equality which depend on the dimension of the singularity set in addition to time and space integrability assumptions; in doing so we improve upon the classical results when attention is restricted to the first blowup time. When our method is inconclusive, we are able to quantify the possible failure of energy equality in terms of the lower local dimension and the concentration dimension of a certain measure associated to the solution. The work described is joint with Roman Shvydkoy (UIC).

Stefan Steinerberger

Wasserstein Distance as a Tool in Analysis

Wasserstein Distance is a way of measuring the distance between two probability distributions (minimizing it is a main problem in Optimal Transport). We will give a gentle Introduction into what it means and then use it to prove (1) a completely elementary but possibly new and quite curious inequality for real-valued functions and (2) a statement along the following lines: linear combinations of eigenfunctions of elliptic operators corresponding to high frequencies oscillate a lot and vanish on a large set of co-dimension 1 (this is already interesting for trigonometric polynomials on the 2-torus, sums of finitely many sines and cosines, whose sum has to vanish on long lines) and (3) some statements in Basic Analytic Number Theory that drop out for free as a byproduct.

Franc Forstnerič

Minimal surfaces by way of complex analysis

After a brief historical introduction, I will present some recent developments in the theory of minimal surfaces in Euclidean spaces which have been obtained by complex analytic methods. The emphasis will be on results pertaining to the global theory of minimal surfaces including Runge and Mergelyan approximation, the conformal Calabi-Yau problem, properly immersed and embedded minimal surfaces, and a new result on the Gauss map of minimal surfaces.

Andrew Zimmer

The geometry of domains with negatively pinched Kaehler metrics

Every bounded pseudoconvex domain in C^n has a natural complete metric: the Kaehler-Einstein metric constructed by Cheng-Yau. When the boundary of the domain is strongly pseudoconvex, Cheng-Yau showed that the holomorphic sectional curvature of this metric is asymptotically a negative constant. In this talk I will describe some partial converses to this result, including the following: if a smoothly bounded convex domain has a complete Kaehler metric with close to constant negative holomorphic sectional curvature near the boundary, then the domain is strongly pseudoconvex. This is joint work with F. Bracci and H. Gaussier.


Extras

Blank Analysis Seminar Template