Van Vleck Notes

 

 

Department of Mathematics ¡ University of Wisconsin - Madison ¡1999

 

http://www.math.wisc.edu

Table of Contents

 

Math Department receives NSF VIGRE Award

 


The Department of Mathematics has received a three-year $1.5 million grant from the National Science Foundation within their VIGRE program: Vertical Integration of Research and Education in the Mathematical Sciences. The VIGRE program was developed by NSF's Division of Mathematical Sciences as a way of increasing the pipeline of domestic students going into mathematics. Besides the demand for mathematicians at universities, there is also a huge demand for well-trained mathematicians in industries.

 

The Department plans to build on its tradition of excellence in graduate education that goes back more than 100 years, with the successful training of approximately 950 PhDs in Mathematics who now occupy important positions in universities and industries throughout the USA and indeed the world. For more than 25 years it has also had a successful postdoctoral program (the Van Vleck program), with more than 80 Mathematics PhDs continuing their training in research and instruction under the mentorship of established researchers and educators.

 

The grant provides funding for undergraduate research and other creative experiences, graduate fellowships, and postdoctoral fellowships. The Mathematics Department's program seeks to sustain, strengthen, enhance, revise, and integrate the various areas of mathematics education at UW-Madison: (1) Mathematics Undergraduate Education, (2) Applied Mathematics, Engineering, and Physics Undergraduate Program (AMEP), (3) Mathematics PhD Program within the Department of Mathematics, (4) Applied Mathematical Sciences Interdisciplinary Program within the Center for Mathematical Sciences, and (5) Postdoctoral Training in Pure and Applied Mathematics.

The goals of the program include: broadening the mathematics education of undergraduate and graduate students, and postdoctoral fellows so that they will be able to interact better and communicate effectively with scientists and engineers, and carry out high&-level mathematical research; strengthening the traditional undergraduate, graduate, and postdoctoral programs in core mathematics; decreasing the time to the PhD degree.

VIGRE graduate fellowships have been awarded to ten graduate students, seven of whom are new students this year. VIGRE postdoctoral fellowships have been awarded to two mathematicians who have just received the PhD. Several faculty members are beginning research projects with undergraduates that are being funded by the VIGRE grant. You can read more about these people inside this newsletter.

 

Some of the highlights of our new initiatives include:

 

A laboratory component in one or more undergraduate courses will be developed that will clearly illustrate the successes and limitations of applied mathematics modeling of physical problems. The experiments would be demonstrations carried out to clearly illustrate points and not to train students for experimentation. Potential courses for such a component are: Applied Dynamical Systems and Chaos, PDEs, Introduction to Applied Mathematics, and undergraduate and graduate Fluid Mechanics.

 

 


An Integrated Undergraduate, Graduate, and Faculty Research Lab in Spatial Systems will be developed. Individually and in groups, students will study various spatial systems from combinatorial and probabilistic perspectives, with some use of computer simulation. Research questions that arise in faculty and postdoctoral fellows research will be described to students who investigate these and other questions that surface in their course of investigation. Possible participants included one or two bright high school students, e.g. students from local high schools who are among the winners of the Wisconsin Mathematics Talent Search.

 

With the effective use of VIGRE funds, we plan to recruit quality American graduate students with offers of traineeships (VIGRE fellowships and Teaching Assistantships); provide graduate students with a quality graduate program, including interdisciplinary training that gives experience in solving practical mathematical problems; reduce the time-to-degree by targeting substantial fellowship money on a small group of students who have the potential of becoming research mathematicians at top universities and labs.

 

Cognizant of the fact that many graduates do not work in academic settings, we plan to widen the scope of the current Mathematics PhD program in the Department of Mathematics, supplying our graduate students with the necessary experience in solving practical mathematical problems. To these ends, we are planning to start an Applied Mathematics Consulting Project. This would take the form of nonstandard graduate courses for mathematics graduate students whose main goal is to set up interdisciplinary cooperation, at a research level, between mathematics graduate students and researchers in other fields at the University. This course will be taught for the first time in the spring by Paul Milewski, with the help of the VIGRE Van Vlecks, Dan Knopf and Chris Raymond. The goals of this project are to foster new connections between researchers in mathematics and other disciplines and to encourage interaction between mathematics graduate students and faculty in other disciplines.

 

A biweekly VIGRE Brownbag Seminar is meeting this semester with participation from faculty, postdocs, graduate students, and undergraduate students. Attendance averages 25 per meeting. The format for the first few meetings has been short talks describing oneÆs research interests or a specific problem. We follow the ôruleö that when someone sits down after talking, someone else gets up and starts talking. At one session, there were four speakers: an undergraduate student, a postdoc, a faculty member, and a graduate student!

 

The VIGRE program is under the leadership of Richard A. Brualdi, Marshall Slemrod, Eric Bach, Thomas Kurtz, Paul Milewski, and Paul Rabinowitz. The grant has been approved on scientific and technical merit for five years, with an additional $1 million expected for years 4 and 5.

1999 Wisconsin Reunion in San Antonio, TX

ANNUAL WISCONSIN REUNION IN WASHINGTON, D.C.

 

The Tenth Annual Wisconsin Reunion of Wisconsin Alumni and Friends will take place at the annual AMS and MAA meetings in Washington, D.C. on Friday, January 21 from 5 to 7 p.m.á The location will be the Embassy Room, in the Omni Shoreham Hotel. As always, there will be hors dÆoeuvres, a cash bar, and lots of interesting talk among good friends. Last year there were more than 75 people at the reunion. As usual, we are requesting a contribution of $5 to help defray the costs.á We hope to see you in Washington!

Upcoming Conferences

Combinatorics of Lie Type in Madison

From June 6 to June 22, 2000, a Conference on Combinatorics of Lie Type will be held in Madison. This conference, being organized by Georgia Benkart, Peter Orlik, and Arun Ram, will honor Louis Solomon for his distinguished career.

 

Invited speakers include: F. Brenti, M. Broue, V. Chari, R. Charney, K. Erdmann, M. Geck, V. Ginzburg, J.C. Jantzen, A. Kleschev, G. Lehrer, P. Littelmann, G. Lustig, O. Mathieu, A. Mathes, A. Okounkov, M. Putcha, M. Reeder, T. Shoji, H. Terao, J. Thibon, M. Wachs, and A. Zelevinsky.

 

Information, including a registration form, on the conference can be obtained, as it becomes available, at the WEB address http//www.math.wisc.edu/~comblie/


Conference on Rings and Algebra

 

From September 8 to 10, 2000 , a Conference on Rings and Algebras will take place in Madison. This conference, being organized by Georgia Benkart and Efim Zelmanov, will honor J. Marshall Osborn for his distinguished career.

 

The invited speakers for this conference are still being determined.

 

More information, including a registration form, on this conference can be obtained, as it becomes available, at the WEB address http://www.math.wisc.edu/events/

 


Letter from the Chair...

It is a pleasure for me to write a few lines for readers of this newsletter. As Chair I have overall responsibility for the "smooth functioning" of the Department of Mathematics at UW-Madison, a task which may seem rather daunting. Fortunately the University of Wisconsin has a tradition of faculty governance, hence in our department real authority lies with the faculty, implemented through various committees. My main role is to exercise a certain amount of "persuasion" and make sure that all the bills get paid on time....

 

This system encourages a great diversity of ideas, and we have no uniform view on research or teaching. Our colleagues are non-conformists, individualistic and downright stubborn - but we wouldn't have it any other way. The "department" is the collective aggregate of numerous individual efforts, which are constantly changing and interacting. This allows us to engage in meaningful and substantive discussions within a traditionally amiable collegial setting. We do, however, all share the basic goals of total intellectual honesty and the relentless pursuit of knowledge - perhaps the two most essential components of any mathematical endeavor.

 

In this issue of the newsletter you will read about recent activities here in Madison. I hope that you will find it interesting and informative. As you will see, our department has taken important steps in renovating its research and teaching programs. We will be facing important challenges in replacing our distinguished older faculty (who have been retiring in large numbers), but this will also be an exciting opportunity to shape the department for years to come.

 

I hope that as a former student or simply as a friend of Wisconsin mathematics you will keep in touch with us, either in writing or by stopping by. For those of you who have provided financial support I wish to thank you for your generosity. Even small amounts have helped provide a "margin of quality" here in Van Vleck and all the faculty and students are deeply appreciative of your support.

 

Alejandro Adem

Chair

Department of Mathematics

 


New Faculty

 

Two new tenure-track assistant professors and one new associate professor were hired last year:

 

Mikhail Feldman

Mikhail Feldman, a new assistant professor, received the PhD from the University of California - Berkeley in 1994; his thesis advisor was L.C. Evans. Feldman's early education, up to a B.A. degree, was in the Ukraine. He was a Lecturer at the University of Pennsylvania from 1994 to 1996 and a postdoctoral fellow at the University of California - Berkeley from 1996 to 1997. From 1997 to 1999 he was Ralph Boas Assistant Professor of Mathematics at Northwestern University.

 

Dr. Feldman works on nonlinear partial differential equations of elliptic and parabolic type, specifically on variational and geometric evolution problems, viscosity solutions, regularity for elliptic and parabolic systems and free boundary problems. He also works on Monge's mass transfer problem and its application to PDE. Mikhail joined us in Madison this fall and is a wonderful addition for our program in Partial Differential Equations.

Ken Ono

Ken Ono, a new associate professor with tenure, received the PhD in Mathematics from the University of California - Los Angeles in 1993, with a thesis written under the supervision of Basil Gordon. He spent one year at the University of Georgia, one year at the University of Illinois at Urbana&-Champaign, and two years at the Institute for Advanced Study, Princeton before assuming a tenure-track assistant professorship at the Pennsylvania State University in 1997. Dr. Ono is on leave this year and will join us in Madison beginning with the fall 2000 semester. Ken is a 1999-2001 Alfred P. Sloan Foundation Research Fellow and also has received a 1998-2004 NSF Career Award (which combines research with educational activities). This year he was selected as one of the twenty-four 1999 David and Lucile Packard Fellows. The Packard Fellowship is a five year award totaling $625,000. Since the inception of the Packard Fellowships, Ken is the 11th mathematician and the 7th UW-Madison faculty member to have received a fellowship.

 

The Number Theory Foundation, a nonprofit organization which provides private research support for research in number theory and which typically funds conferences, decided this year for the first time to award a Number Theory Foundation Postdoctoral Fellowship. Ken won the right to offer the position, a two year postdoctoral fellowship (with a possible extension to a third year) which comes with a teaching load of two courses per year.

 

Ono's primary research interests are in number theory. He works on questions related to elliptic curves, modular forms and partitions. His recent work on partitions, which he describes as "breaking a number up into sums" has led to surprising new perspectives on the deeper structure of connections between partitions and more complicated abstract objects in arithmetic geometry. With the recent solution of the 350 year old "Fermat's Last Theorem" problem, number theory has solidified its position as one of the most publicly visible areas of mathematics. Modern applications of number theory to reliable transmission of information (error-correcting codes) and the secure transmission of information (crypto-graphy) have brought new urgency to research in number theory.

Patrick Speisseger

Patrick Speissegger, a new assistant professor, received the PhD from the University of Illinois in 1996 with a thesis in the area of model theory and its applications to real algebraic geometry, written under the supervision of L. van den Dries. He was a Postdoctoral Fellow at The Fields Institute in Toronto in 1996-97. Since 1997 he has been a Postdoctoral Fellow at the University of Toronto, with a six months leave spent at the Mathematical Sciences Research Institute (Berkeley) in 1998. At Toronto, Patrick is credited with turning around a "moribund" third-year logic course (aimed at students not specializing in mathematics).

 

Dr. Speissegger's research lies in the general areas of model theory and real algebraic geometry. The notion of o-minimal expansion of the field of real numbers provides a suitable setting for studying generalizations of the theory of semialgebraic sets, and he is interested in finding new explicit examples of such expansions.


During his years as a graduate student at the University of Illinois, Patrick constructed two such examples in joint work with Lou van den Dries. Both expand the structure of globally subanalytic sets and define the exponential function; moreover, one of them also defines the Riemann zeta function on all real numbers greater than 1, while the other defines the Gamma function on all positive real numbers.

 

More recently, building on work by Alex Wilkie as well as by Jean-Marie Lion and Jean-Philippe Rolin, he showed that any o-minimal expansion R of the field of real numbers has in turn an o-minimal expansion P(R), called the Pfaffian closure of R, that is closed under taking solutions to Pfaffian equations. He is currently working with Jean-Marie Lion and Chris Miller, to study further properties of such Pfaffian closures of o-minimal structures. Patrick will join us in Madison for the spring semester of the current academic year.

The total number of new faculty hired in the last five years is now ten: Yongbin Ruan, Paul Milewski, Leslie Smith, Fabian Waleffe, Eleny Ionel, James Propp, Arun Ram, Mikhail Feldman, Ken Ono, and Patrick Speisseger. With many more new faculty to be hired in the next several years, there are a lot of changes taking place in Van Vleck Hall.

Van Vleck Visiting Assistant Professors

 

Five recent PhDs accepted three-year appointments this past year as Van Vleck Assistant Professors: Markus Banagl, Dan Knopf, Rajesh Kulkarni, Christopher Raymond, and Bo Su. In addition, Jonathan Pakianathan who had been a Lecturer for two years accepted a one-year appointment as a Van Vleck Assistant Professor. Anne Shepler, who has a two-year NSF Postdoctoral Fellowship, also received a half-time Van Vleck Assistant Professor appointment for the academic years 2000-01 and 2001-02.

Markus Banagl received the PhD from the Courant Institute of Mathematical Sciences in 1999 with a thesis "Extending Intersection Homology Type Invariants to non-Witt Spaces" written under the direction of Sylvan Cappell. His research interests are in extending generalized Poincare duality and intersection homology to non-Witt spaces.


Dan Knopf received the PhD from the University of Wisconsin - Milwaukee in 1999. His thesis, under the direction of Kevin McLeod, was titled "Quasi-convergence of the Ricci flow." His research interests are in PDE and differential geometry, particularly geometric evolution equations - the nonlinear heat equations which give rise to curvature flows. His area of first interest is the Ricci flow. Dan is one of our VIGRE Van Vlecks, being partially supported by the Department's VIGRE Grant from NSF.

Rajesh Kulkarni received the PhD in 1999 from Indiana University. His thesis "Clifford algebra of binary forms" was written under the direction of Valery Lunts. His research interests are in representation theory of quantized deformations of algebras, geometric approach to Azumaya algebras and Brauer groups, and number theory related to these issues. Rajesh is spending the fall semester at MSRI (Berkeley) on a fellowship and will join us in the spring semester.


Christopher Raymond received the PhD in Applied Mathematics in 1999 from Northwestern University where his advisor was Bernard Matkowsky. The title of Christopher's thesis was "Melting Effects in Condensed Phase Combustion with Applications to Combustion Synthesis of Materials." His research interests are in combustion modeling where he uses techniques of asymptotic/singular perturbation analysis of nonlinear parabolic systems, combined with numerical simulations using adaptive Chebyshev pseudospectral methods. Chris is also a VIGRE Van Vleck, being partially supported by the Department's VIGRE Grant from NSF.

 

Bo Su also received the PhD in 1999 from Northwestern University. His thesis title was "Existence of L\infty solutions for Hamilton-Jacobi equations," and his advisor was G-Q. Chen. His research interests include Hamilton-Jacobi equations, compressible NavierStokes equations, hyperbolic conservation laws, and Monge-Kantorivich mass transfer problems.

Jonathan Pakianathan, who has been at UW-Madison since 1997, received the PhD from Princeton University in 1997. His advisor was William Browder. His research interests are in algebraic topology, group cohomology, Lie algebras, and group actions. Recently he provided a striking counterexample to a conjecture of A. Adem that the highest torsion in the integral cohomology of a finite p-group should occur infinitely often. He has been a very successful and popular teacher here for two years.

 

Anne Shepler received the PhD from the University of California - San Diego in 1999 with a thesis "Semi-invariants of finite reflection groups" written under the direction of Peter Doyle. Her research interests are in geometry and algebra, specifically finite reflection groups, invariant theory, and hyperplane arrangements. Anne has received an NSF Postdoctoral Fellowship (her mentor is Peter Orlik) and is concentrating on research this year. In 2000-01 and 2001-02 she will be teaching half-time as a Van Vleck Assistant Professor.


Promotions

 

Four assistant professors were promoted to associate professor with tenure. They are Paul Milewski, Fabian Waleffe, James Propp, and Arun Ram. In addition Associate Professor Yongbin Ruan has been promoted to (full) Professor.

Paul Milewski

Paul Milewski received a PhD in Applied Mathematics from MIT in 1993 and wrote a thesis under the direction of David Benney. After two years as Gabor Szego Assistant Professor at Stanford University, where his mentor was Joe Keller, he joined UW-Madison as Assistant Professor in 1995. Paul was an Alfred P. Sloan Research Fellow in 1997-99 and a UW-Madison Lilly Teaching Fellow in 1997-98. Under the latter he developed a course in Applied Dynamical Systems; in this course, he successfully introduced the use of computers for visualization, with the students using programs that he developed for mathematical experimentation. That course is now a regular part of our offerings.

 

 

Dr. Milewski is an applied mathematician specializing in asymptotic and numerical methods in fluid mechanics and wave propagation. His goal is to understand complicated physical phenomena using mathematical analysis and scientific computation. Paul has developed a new isotropic equation for three dimensional water waves and has found striking new phenomena for vortical flow in deep and shallow water. With colleague Jean-Marc Vanden-Broeck, he classified the possible singularities which can arise on a free-surface; new axisymmetric singularities and a generalization of the Stokes angle were found. They also did a numerical study of the generation of gravity capillary solitary waves at the front of an object moving below a free surface. Recently, he has been working on nonlinear waves in several dimensions, developing novel numerical schemes to compute solutions of the equations.

 

Fabian Waleffe

Fabian Waleffe received the PhD in Applied Mathematics from MIT in 1989. He was a Postdoctoral Research Fellow at the Center for Turbulence Research (Stanford University) from 1989 to 1992. He then returned to MIT as Lecturer (1992-94) and Assistant Professor (1994-98). He came to UW-Madison as an Assistant Professor of Mathematics and Engineering Physics in spring of 1998.

 

Dr. Waleffe's primary research area is fluid dynamics, and he focuses on issues related to the phenomenon of turbulence. He is interested in computational, perturbative, and rigorous approaches to the problem, as well as in developing simple models of the main processes. More generally, his interests are in physical dynamical systems with applications in mechanical and aerospace engineering and geophysics. FabianÆs current research aims at elucidating the onset of turbulence in shear flows, such as flows in pipes and channels. He has identified a nonlinear process that appears to be the main ingredient responsible for the bifurcation of shear flows and the maintenance of turbulence. This process, suggested by a massive amount of experimental visualizations of "coherent structures." He formulated that self-sustaining nonlinear process and demonstrated its plausibility through careful analysis. One of his current objectives is to fully characterize the bifurcations that lead to a turbulent flow. Dr. WaleffeÆs appointment is 75% in mathematics and 25% in engineering physics (College of Engineering).

 

James Propp

After receiving the PhD in 1987 from the University of California - Berkeley, James Propp spent one year as a Visiting Professor at the University of Maryland and two years as an Adjunct Assistant Professor at Berkeley. He was on the faculty at MIT from 1990 to 1998 (with leave at the Mathematical Sciences Research Institute in Berkeley in the falls of 1992 and 1996). Jim was appointed assistant professor at UW-Madison beginning with the 1998-99 academic year but spent the 1998-99 academic year as a Visiting Scholar at MIT, working on a book on the Solution of FermatÆs Last Problem and continuing with his research program.

 

Propp's research is broad and inter-disciplinary. He has made contributions to probability (Markov processes, ergodic theory), combinatorics (plane partitions, number theory, graph theory, mathematical games), random tilings, and integer programming. His work combines many subfields of mathematics and impacts Computer Science and Statistical Mechanics. Together with his student David Wilson, Jim invented an algorithm known as Coupling From The Past. This simple and beautiful idea leads to a means of obtaining reliable samples from the (exact) stationary distribution of a Markov chain. A second major area to which Propp has contributed is random tilings. These problems arise in statistical mechanics and the study of quasi-crystals. Propp and others proved a conjecture about the deterministic limiting shape of a random tiling of a planar region called the Aztec Diamond. Their result is that there is a region of complete order and a region of random orientation, and that the boundary between the phases is exactly circular.

 


In addition, to his research, Jim has a multifaceted teaching record. At MIT he worked extensively in his Tiling Lab with undergraduates, who produced good and publishable mathematics. Since joining us in Madison for the fall semester this year. he is laying the foundation to recreate this Lab here in Madison. As a way of getting to know undergraduates (and for undergraduates to know him), he is taking an active role in the Undergraduate Math Club. Next June, Jim will be an invited speaker at the Formal Power Series & Algebraic Combinatorics (FPSAC) Conference held at Moscow State University in Russia.

 

Arun Ram also became an assistant professor at UW-Madison beginning with the 1998-99 academic year. He received the PhD in 1991 from the University of California - San Diego, spent one year at MIT on an NSF Postdoctoral Fellowship, held a Van Vleck Assistant Professorship at Wisconsin from 1992 to 1995 (partially supported by the same Fellowship), and was Assistant Professor at Princeton University from 1995 to 1999. He was on leave in 1995-96 at the University of Sydney with an Australian Research Council Senior Research Fellowship. Arun joined us in Madison beginning with the fall semester of the 1999-2000 academic year. At Princeton he was co-director of the Graduate Studies Program.

Arun Ram

Dr. Ram's research is at the interface between combinatorics and representation theory. He is an expert on Hecke algebras, which have important connections with combinatorics, representation theory, algebraic geometry, and number theory. He has determined the characters of the finite-dimensional Hecke algebras and Brauer algebras, constructed the irreducible representations of affine Hecke algebras, and found a remarkable generalization of the fundamental combinatorial notion of a Young tableau. ArunÆs formulas for the characters of the Brauer algebra have played a critical role in the theory of random orthogonal matrices in statistics, a topic with connections to the long-standing problem of determining the zeros of the zeta function.

 

Yongbin Ruan

Yongbin Ruan received the PhD from the University of California - Berkeley in 1991. Before joining our faculty as an Associate Professor in 1995, he was a Research Instructor at Michigan State University (1991-93) and Assistant Professor at the University of Utah (1993-96). Professor Ruan was awarded a Sloan Research Fellowship (1995-97). In 1998 he gave an invited lecture at the International Congress of Mathematicians.

 

Dr. Ruan's research area is geometry & topology and, increasingly so, mathematical physics. His presence at Madison has contributed enormously to the vigorous renewal of our program in geometry & topology. His work is at the forefront of one of the most active areas of mathematical research. Yongbin is founder of a new and important theory called quantum cohomology, which is used to define invariants for classifying symplectic manifolds. With An-Min Li he found the first instances of geometric maps which induce isomorphisms or homomorphisms (preserving algebraic structure) of quantum cohomology. The maps that they discovered belong to the subject of birational geometry, and one of Ruan's programs is to understand the deep relationship between quantum cohomology and birational geometry. His second major program is the solution of two conjectures in algebraic geometry - the Mumford conjectures concerning characterization of rational surfaces in higher dimensions by purely cohomological conditions. These conjectures fit into RuanÆs quantum cohomology theory, and their solution may lie in physics, which is the origin of quantum cohomology.

 

 

Melinda Certain Granted An Indefinite Appointment

Melinda Certain

Melinda Certain (PhD 1974, R. Askey), who has been a Faculty Associate in the Department of Mathematics since 1988, was recently granted an indefinite appointment. As the name suggest, an indefinite appointment has permanent status and is for an indefinite term; it is the analogue of tenure for academic staff appointments. Dr. Certain is the coordinator of the very successful Wisconsin Emerging Scholars Program (WES) whose main goal is improved success in calculus for minorities and other groups of people which historically have been under-represented in advanced mathematics, science, and engineering. The program, open to all qualified students, recruits minority and rural students (defined to be students from small graduating classes). A major part of this recruiting takes place in the summer when new freshmen come to Madison for the Summer Orientation and Registration Program.

 

In addition to the crucial leadership role in WES, Melinda also teaches one course each semester and engages in important outreach activities involving area public schools. Included among these is the UW Mega Math Meet for 5th and 6th graders in rural Dane County (outside of Madison). Eight regional meets lead to the Mega Math Meet in Madison, typically in May, at which eight teams vie for three trophies. The math-ematics enthusiasm and excitement at these meets is something worth experiencing. It has become traditional for the Chair to greet the students and their teachers and to pose a problem, requiring some insight. At the last two meets, one bright student - much to the surprise of the chair - solved the posed problem in just a few minutes! The student was awarded an elementary math book as a prize.


Visiting Faculty

 

As usual, we have a number of visiting faculty this year, who are teaching and collaborating in research with our mathematics faculty.

 

Fall Semester Teaching Visitors include:

 


Michael Benedikt from Bell Laboratories (Naperville, Illinois). Dr. Benedikt (PhD 1993, H.J. Keisler) is one of our recent alumni. His field of interest is mathematical logic.

 

Rodney Downey from Victoria University of Wellington (New Zealand). Professor Downey received the PhD from Monash University (Australia) in 1982. His research area is logic and computability theory.

 

Joan Hart from the University of Dayton (Ohio). Professor Hart (PhD 1996, K. Kunen) is also one of our recent alumni. Joan spent three years at Union College in Schenectady (New York) as a postdoctoral research and teaching fellow. Her fields of interest are set theory and mathematical logic.

Istvan Juhasz of the Mathematical Institute of the Hungarian Academy of Sciences (Budapest). Professor Juhasz, a frequent visitor to Madison, works on set theory and mathematical logic.

 

Professors Benedikt, Downey, Hart, and Juhasz are lecturing to graduate students in logic at different times throughout the fall semester.

 

Edward Keppelmann of the University of Nevada - Reno. Professor Keppelmann (PhD 1991, E. Fadell) is also an alumnus of Madison. Ed's research field is algebraic topology, especially fixed point theory. He is associate chair of the Mathematics Department at Reno.

 

 

Yiming Long of the Nankai Institute of Mathematics, Nankei University (P.R. of China). Professor Long (PhD 1987, P. Rabinowitz) is Dean of the College of Mathematics at Nankei University. His fields of interest include partial differential equations, dynamical systems, global analysis, and symplectic geometry.

 

Ernesto Vallejo-Ruiz of the Instituto de Matemßticas, UNAM (Mexico). Professor Vallejo-Ruiz received the PhD from the Heidelberg University in Germany in 1988. His fields of interest are representation theory of groups, algebraic combinatorics, and algebraic topology. Ernesto has also received a Fulbright Grant from the J. William Fulbright Foreign Scholarship Board.


Spring Semester Teaching Visitors include:

 


Sergey Bolotin of Lomonosov Moscow State University. Professor Bolotin, a frequent visitor to Madison - he last taught at UW-Madison in 1996, received the PhD in 1982 from Lomonosov Moscow State University. Sergey's main scientific interests lie in dynamical systems, variational methods, Hamiltonian systems, and stability theory.

 

Sergey Ivashkovich of the University Lille-I (Villeneuve d'Ascq, France). Professor Ivashkovich received the PhD from Moscow State University in 1983 and the Doctor of Science from the Steklov Institute (Moscow) in 1994. His areas of research interest include extension properties of meromorphic and holomorphic mappings, singularities of holomorphic bundles, and pseudo-holomorphic curves in complex and symplectic geometry.


 

Honorary Fellows

 

As usual a number of individuals have come to Madison for all or part of the academic year to work with our faculty. Those appointed as Honorary Fellows this year are given below, along with the dates of their stay in Madison, their home institution, and sponsoring faculty member.

 

Choi, Jeongwhan, 1/20/99-2/28/2000, Korea Univ. (M. Shen)

Dolfi, Silvio, Sem. 2/ 99-2000, Univ. of Florence (I.M. Isaacs)

Hirschfeldt, Denis R., 8/15/99-9/30/99, Cornell Univ. (S. Lempp & R. Solomon)

Imay, Martha T., 8/29/99-9/13/99, Ciudad Univ., Mexico (H. Schneider)

Li, Anmin, 9/1/99-12/31/99 Sichuan Univ, P.R. China (Y. Ruan).

Melian, Jorge, 3/2000-12/31/2000, Univ. of La Laguna, Spain (S. Angenent)

Moreto, Alexander, 8/1/99-12/31/99, Univ. del Pais Vasco, Spain (I.M. Isaacs)

Sangroniz Gomez, Josu, 11/1/99-12/5/99, Univ. del Pais Vasco, Spain (I.M. Isaacs)

Tam, Bit-shun, 8/21/99-9/6/99, Tamkang Univ., Taiwan (H. Schneider)

Wieczorek, Wojciech, 7/28/99-7/28/2000, (Y. Ruan)

Wolf, Thomas (PhD 1977, I.M. Isaacs), academic year, 1999-2000, Ohio Univ. (I.M. Isaacs)

Zhiming, Jiang, 12/16/99-12/15/2000, E. China Univ. of Sci. & Tech., P.R. China (R. Brualdi)


Sabbaticals and Leaves

 

Three faculty members are on sabbatical for all or part of the academic year.

 


Robert E.L. Turner is on sabbatical all year studying and doing research in the Department of Applied Mathematics of the University of Pisa (Italy). He is working on applications of mathematics to neuro-physiology. One aspect of the work is the continuation of his project of modeling the neural control of locomotion in the parasite Ascaris suum. Another aspect is the development of a ôPrimer of Mathematics for Neurosciences for instructional purposes. Bob was the Graduate Co-ordinator in the department for the years 1996-99.

 

Anatole Beck is also on sabbatical all year at the London School of Mathematics (England) where he has been a frequent visitor. He is working there on the Rendezvous Search Problem (RSP) with Steve Alpern. The RSP involves the optimal way for two searchers to find each other along a linear course such as a road or river. Anatole hopes to involve undergraduate and graduate students in research on the RSP upon his return.

 

Joel Robbin will be on sabbatical in the spring semester at the ETH (Zurich) working with Dietmar Solomon. They will be studying the relations between (phase space) path integrals and symplectic geometry. Joel hopes to become more knowledgeable about the interface between mathematics and physics, knowledge that he can effectively use in his undergraduate and graduate teaching.

 

In addition to these sabbatical leaves, a number of other faculty are on research leave during this academic year. Georgia Benkart will be at MSRI (Berkeley) in the spring semester, participating in their algebra program. Yong-geun Oh is on leave again this year, spending the fall semester at RIMS, Kyoto University (Japan) and the spring semester at the Korean Institute for Advanced Study (KIAS) in Seoul (Korea). Jean-Marc Vanden-Broeck has a second year leave at the University of East Anglia (England). Stephen Wainger will be on leave at Princeton University in the spring semester. Robin Pemantle is on leave this year at Stanford University.

 


 

Jean-Marc Vanden-broeck

Tea with Jean-Marc Vanden-Broeck

 


Waiting in the grocery check-out line last winter and reading the National Enquirer to compensate for the boredom, you may have been surprised to come to page 51 and see the headline:

 

Nutty Professor Spends $720,000

To Stop Teapots from Dribbling,

with a picture of "wild-haired math professor" Jean-Marc Vanden-Broeck pouring a cup of tea from a dribbling (of course) teapot.

 

Jean-Marc, who has been on leave from UW-Madison these last two years at the University of East Anglia (Norwich. England), studies fluid flows. This study naturally led him to the ôriddleö of why tea dribbles down the underside of a teapotÆs spout, rather than pouring cleanly. The $720,000 refers to the research support Vanden-Broeck has received from government agencies to conduct research on fluid dynamics.

 

According to Vanden-Broeck, after spending a month applying his fluid flow techniques to studying the dribbling tea phenomenon: Tea, or any fluid, dribbles down any design or shape of pot or pouring apparatus. He discovered that the pressure in the fluid underneath the spout is very low. The fluid therefore gets pushed on to the spout by natural atmospheric pressure. Professor Vanden-Broeck's work applies to all fluid movement and has application to a variety of situations where liquid hits a hard surface such as the resistance of waves to a ship's hull.

 

This dribbling teapot story was also featured in a WEB-site ITN Online where the following quotes occurred:

 

From the marketing manage of the British Tea Council: ôWe welcome the professorÆs findings, and if he finds a cure for dribbling teapots that would really be fantastic.ö

 

From a spokeswoman for china teapot makers Wedgewood: ôThe art of pouring still tea still rests with the pourer, no matter how fine the teapot is.ö (Obviously, this person does not appreciate the scientific method.)

 

From a spokesman for Britain's Department for Trade and Industry: "If it is true, we congratulate the professor on his discovery. I am sure tea drinkers around the land tonight owe him a vote of thanks."o:p>

 

From the marketing communications manager of Twinings Tea: "My family has been pondering many aspects of the fine institution of tea drinking for 300 years, but I must confess the dribbling spout phenomenon has not been on that agenda. But it does come as a great relief to know that we can now sit back and enjoy a cup of tea without the frustration of wondering why the teapot dribbles."

 

Is it possible to design the "perfect teapot?" Jean-Marc thinks so but he needs to do more work to calculate the correct proportions. If he is successful, our expectations are that he will then become Sir Jean-Marc.


Potluck Dinner Honors Retirees

 


Our traditional Department Potluck Dinner was held on April 24, 1999 in the ninth floor lounge of Van Vleck Hall. As usual, the occasion was very warm and supportive, with a large turnout and a wonderful feast of culinary creations by faculty and spouses.

 

The gathering also gave an opportunity to recognize the full retirements of three longtime colleagues: Fred Brauer, Seymour Parter, and Hans Schneider. The then chair recalled the career of each of the retirees with some more personal remarks provided by others.

 

FRED BRAUER received the PhD from MIT in 1956. He taught at the Universities of Chicago and British Columbia before joining UW-Madison in 1960. He was chair of the Department from 1979 to 1982. He officially retired in 1996 and began post-retirement service which, to our loss, he ended early at the end of the 1998 fall semester.

 

Fred's research interests have been and continue to be in differential equations and population biology, studying and modeling population growth, predator-prey systems, and infectious diseases. For many years Fred was the department's connection with the biologists scattered all over this campus. He has worked on the development of many courses in the department, including most recently two courses on probability and dynamical systems for biologists, courses which we believe will turn out to become standard fare for biology. Fred has co-authored six textbooks and, in addition, authored a research monograph. Seven students completed PhD dissertations under his guidance.

 

Carlos Castillo Chavez
and others

Fred was devoted to the department and readily volunteered to serve on committees and to teach wherever he was needed. As most everyone knows, Fred and Esther have moved to British Columbia to be near one of their children and family. The result is that we don't get to see Fred and Esther as much as we'd like to. But we do expect regular visits.

 

Bob Wilson provided some personal remarks about Fred, as did Carlos Castillo Chavez, FredÆs 4th PhD student, who came from the IMA in Minneapolis with his family to be with Fred and us that evening.

 

SEYMOUR PARTER received the PhD from New York University in 1958, writing a thesis under Lipman Bers. After two years at Indiana University and three years at Cornell, he came to Madison in 1963 with appointments in both Mathematics and Computer Sciences. He officially retired in 1996 and did post-retirement service for three years until it ended in the fall of 1998. Seymour was chair of the Computer Sciences Department from 1968 to 1970.

 

Seymour's research interests have been in applied and computational mathematics. His research has been broad and influential including contributions to iterative methods for the numerical solution of PDEs, eigen- and singular-values of Toeplitz forms, one of my favorites - analysis of Gaussian elimination using graph theory, and norms and spectral equivalence of elliptic PDEs. I was pleased to have the opportunity to contribute to a joint paper with Seymour during my first year here at Wisconsin. I still have a vivid memory of that year when so many math faculty were living in University Houses.

 

Seymour took on many important national responsibilities during his long career: President of SIAM, Chair of the Conference Board of Mathematical Sciences, and the Committee on the Undergraduate Program in Mathematics, Managing Editor of the SIAM Journal on Numerical Analysis, to name a few. A special issue of this journal was dedicated to Seymour on the occasion of his 65th birthday. Thirteen students have written dissertations under his supervision, some in Mathematics and some in Computer Sciences.

 

I view Seymour as one of the wise people in the Department who one could always count on for penetrating insight at department meetings and other occasions. Seymour and Ruth are expert skiers, downhill and cross-country, with Ruth's passion for dancing complementing Seymour's passion for running.

 

Jake Levin provided some personal reminiscences, and took advantage of the chair's request to provide such remarks which included these words: ôI must admit that you were not the first person to come to mind in this case. But Carl de Boor is out of town and so are Marshall Slemrod and Si Hellerstein.ö Jake's particular way to tell us he was fourth choice resulted in great laughter.

 

HANS SCHNEIDER received the PhD in 1952 at the University of Edinburgh with a thesis written, at least nominally, under A.C. Aitken. According to Hans, he received essentially two words of advice from Aitken: READ FROBENIUS. Those of us who know Hans well know he took this advice to heart; he even called his computer Frobenius. This was good advice that shaped HansÆ mathematical career. After seven years at Queens University in Belfast, including one year on leave at Washington State, Hans joined our mathematics department in 1959. He served as chair of the Department from 1966 to 1968. In 1988 he was named James Joseph Sylvester Professor of Mathematics. Hans officially retired in 1993 but continued post-retirement service which ended in the fall of 1998.

 


Hans has been an active and influential linear algebraist for nearly 50 years - an enormous length of time. The different areas of linear algebra to which he has made fundamental contributions are many: nonnegative matrices, M-matrices, norms, numerical ranges, combinatorial and graph-theoretic matrix theory, Jordan and spectral theory, inertia and stability theory, matrix scalings, cone preserving maps, matrix polytopes, ... . I can't think of any more influential or more important linear algebraist in this century.

 

Hans became editor-in-chief of the journal ôLinear Algebra and its Applications (LAA) in 1972 and he developed it into a major mathematics journal. He was instrumental, indeed the driving force, in the creation of ILAS, the International Linear Algebra Society. He was the founding president of the Society and served as president from 1987 to 1996. It was with some trepidation that I assumed the ILAS presidency in 1996 because of the risk involved in following in his giant footsteps.

 

Sixteen students have written dissertations under Hans' guidance, with one more yet to come. Two of them, Bob Wilson and Yvonne Nagel, are here tonight, his 7th and 9th student, respectively.

 

Throughout his career, Hans has enjoyed enormous support from his wife Miriam. She has managed to give this and at the same time have a remarkable career as a Madison violinist and violin teacher.

 

Marshall Osborn provided some anecdotes about Hans and Miriam and their early years together in Madison.

 

John Nohel, being in Zurich, sent some personal and congratulatory remarks about each of the retirees to be read at the gathering.

 

Each of Fred, Seymour, and Hans has contributed immeasurably and in different but important ways to this department and our lives in it. Each of them has been with us for nearly forty years - Fred for 38, Seymour for 36, Hans approaching 40. We owe them a debt of gratitude.

 

Seymour Parter, Richard Brualdi,
Hans Schneider, and Fred Brauer

After noting the recent and impending birthdays of the retirees and other distinguished people present, the ôtraditionalö birthday cake went to Mary Ellen Rudin who celebrates her 75th birthday on December 7, 1999. A rousing rendition of Happy Birthday To Everyone (!) closed this part of the program. The program itself closed with some remarks by Alex Nagel, Don Passman, and Hans Schneider about the retiring chair, Richard Brualdi.

 

 

Larry Levy, who announced his retirement too late to be included in the festivities reported above, retired from active teaching in May, 1999. This academic year he is spending much of his time traveling and working with collaborators (normally via email). He will spend one month at MSRI in Berkeley, three months at the University of Leeds (England), and will also make shorter visits to Italy and Mexico.

 

Larry Levy received the PhD in 1961 from the University of Illinois, after receiving both a B.S. (1954) and M.S. (1956) from the Juilliard School of Music. He began his professional mathematical career in 1961 with an appointment as Assistant Professor, becoming Professor in 1971. He spent 38 years at UW-Madison, including one year as Visiting Professor at Wayne State University in 1989-90.