| MathStat Home | USA Home |
| Date/Time | Speaker | Title/Abstract |
|---|---|---|
| Thursday April 29, 1999 3:30 in ILB 370 |
Lisa Fauci Tulane |
TBA |
| Abstract: TBA | ||
| Thursday April 22, 1999 3:30 in ILB 370 |
Alexander Kleshchev Univ. of Oregon |
Representations of the symmetric group which are irreducible over subgroups |
| Abstract: We will talk about the following problem: Describe all pairs (G,D), where D is an irreducible module over the symmetric group Sym(n) and G is a proper subgroup of Sym(n) such that the restriction of D to G is irreducible. | ||
| Tuesday April 6, 1999 3:30 in ILB 370 |
Mike Kelly Loyola, N.O. |
Fixed Point Index Bounds and Finite Aspherical Complexes |
| Abstract: Given a class of topological spaces and a class of continuous self-mappings defined on these spaces, it is sometimes possible to get information about the fixed points of the mapping. For example, for linear maps of k-dimensional tori, the index of an isolated fixed point must be ˜1, and also, each has the same index. This paper presents two recent results along this line, and some possible generalizations are discussed. | ||
| Thursday April 1, 1999 3:30 in ILB 370 |
John Dean |
The Simplest Hyperbolic Knots |
| Abstract: TBA | ||
| Tuesday March 30, 1999 3:15 in ILB 370 |
Iuliana Oprea Arizona State |
Polar Reversals and Sunspots: The Nonlinear Convective Dynamo |
| Abstract: TBA | ||
| Friday March 30, 1999 1:00 in ILB 350 |
Ulrich Koschorke Siegen, Germany |
Milnor's mu Invariant and Higher Dimensional Link Homotopy |
| Abstract: TBA | ||
| Friday March 26, 1999 3:30 in ILB 370 |
Joe Borzellino Penn St. - Altoona |
Orbifolds with Lower Ricci Curvature Bounds |
| Abstract: TBA | ||
| Thursday March 25, 1999 3:30 in ILB 370 |
Xiao-Song Lin UC-Riverside |
On the Melvin-Morton Conjecture |
| Abstract: This talk will survey three different proofs of the Melvin-Morton conjecture about a remarkable relationship between the colored Jones polynomial and the Alexander polynomial. One (non-rigorous) proof was given by Rozansky using Witten's Chern-Simons path integral. The first rigorous proof was given by Bar-Natan and Garoufalidis using Kontsevich integral, with simplifications given later by Vaintrob and Chmutov independently. And the third proof was given by Lin and Wang based on a model of random walk on knot diagrams. All three proofs trace the Melvin-Morotn conjecture back to some more general identities in different fields. | ||
| Friday March 19, 1999 3:00 in ILB 370 |
Bikas K. Sinha Univ. of Maryland |
Comparison of Experiments |
| Abstract: This talk will illustrate the concept of sufficient experiments through some simple examples relating to Binomial and Poisson Distributions. Comparison of normal populations will also be made to reveal interesting results. | ||
| Monday March 15, 1999 3:30 in ILB 370 |
Vsevolod Lev Hebrew University |
Linear equations over F_p and moments of exponential sums |
| Abstract: TBA | ||
| Monday March 15, 1999 2:00 in ILB 430 |
Krishnendu Mukhopadhyaya, Univ. of Florida |
Analysis of Finite Buffered Synchronous MIN Under Non-uniform Traffic Model With Combinable Requests |
| Abstract: TBA | ||
| Thursday March 4, 1999 3:30 in ILB 370 |
Xenia Kramer Virginia Tech |
Groebner Bases in Noncommutative Rings |
| Abstract: The fundamental tool of computational algebra is the theory of Groebner bases. A Groebner basis of an ideal I is a set of generators for I which allows us to determine whether a given polynomial f is an element of I. The development of Groebner bases and the availability of powerful computers have made symbolic computation in polynomial rings more feasible. These methods have proved especially useful in commutative algebra and algebraic geometry for developing algorithms to augment previously known pure existence proofs. For example, effective methods are known for computing the radical of a given ideal and for finding the minimal decomposition of a given variety. Groebner basis theory for noncommutative rings is a relatively new area; however, it is already clear that having a Groebner basis for an ideal of a noncommutative ring is a powerful tool. We discuss the theory of Groebner bases in noncommutative rings and its connection to rewriting systems in groups. As an application, we develop a criterion sufficient to determine when a certain class of noncommutative rings is Noetherian. Finally, we discuss some difficulties in the computation of Groebner bases which are inherent in the move from the commutative to the noncommutative case. | ||
| Wednesday March 3, 1999 3:30 in ILB 370 |
Serge Troubetzkoy UAB |
Applications of Symbolic Coding to Smooth Dynamical Systems |
| Abstract: Several of my results which seem
quite different are linked by a common method of proof: symbolic coding. I
will begin by giving a quick overview of this method and a simple example. Then I
will present two of my results. 1) Billiards in polygon: A periodic billiard orbit clearly does not accumulate at any vertex. This turns out to be a characterization of periodic orbits (i.e. all non-periodic orbits do accumulate at at least one vertex). I will talk about this result and some of its implications. 2) Surface diffeomorphism with positive topological entropy: I will talk about a special symbolic coding which allows one to get the best known lower bound on the growth rate of periodic orbits. |
||
| Tuesday March 2, 1999 3:30 in ILB 370 |
Evelyn Sander | Phase Separation in Binary Alloys |
| Abstract:
The Cahn-Hilliard equation provides a model for the formation of metal alloys. One
particularly intriguing phenomenon is spinodal decomposition: if a homogeneous
high-temperature mixture of two metallic components is rapidly cooled to a lower
temperature, then a sudden phase separation can set in. That is, the mixture becomes inhomogeneous and forms a fine-grained structure, more or less alternating between the two metal components. This talk presents numerical simulations and subsequent analytical results, carried out jointly with Thomas Wanner, which have lead to a new approach to understanding the underlying mechanism for spinodal decomposition. |
||
| Thursday February 25, 1999 3:30 in ILB 370 |
Mark Carpenter | Introduction to the Generalized Linear Model |
| Abstract: In this talk, we will introduce the concept of the generalized linear model. It will serve as the first of a series of talks on this subject. It is hoped that this seminar series will create research interests among the math/stat faculty. These models have gained a lot of popularity in recent years, not only in the theoretical research literature but in the area of statistical applications as well. Of particular interest for Dr. Shah and me, is the Poisson regression model. Specifically, we wish to address the limitations of the model building diagnostics for fitting the Poisson regression model to the counts of extreme-events data. For example, the Pearson’s Chi-square and the likelihood-ratio Chi-square statistics often lead to contradictory results, i.e., the reported p-value is extremely large for one while extremely small for the other. | ||
| Thursday February 18, 1999 3:30 in ILB 370 |
Vasily Prokhorov Univ. South Alabama |
On Rational Approximation, S-numbers, and the AAK Theorem |
| Abstract: Questions concerning the theory of Hankel operators will be considered. The theory of Hankel operators is a valuable tool in approximation theory for investigating extremal problems such as best approximation of analytic functions by rational functions. In particular, with help of Adamyan-Arov-Krein theorem, it is possible to investigate degree of rational approximation for different classes of analytic functions. The Adamyan-Arov-Krein theorem permits the investigation of the degree of rational approximation of analytic functions to be reduced to that of the rate of decrease of singular numbers of the appropriate Hankel operator. | ||
| Thursday February 11, 1999 3:30 in ILB 370 |
Hans-Hermann Bock Aachen, Germany |
Cluster Analysis and Neural Networks |
| Abstract: Clustering methods are designed to partition a given set of objects, whose properties are described by data or feature vectors, into a suitable number of classes (`clusters') which are homogeneous with respect to those properties. Typical approaches formalize the clustering problem as an optimization problem which is solved, e.g. by combinatorial algorithms such as k-means, exchange algorithms, genetic algorithms or simulated annealing. This paper show how neural networks can be used for solving clustering problems. It deals primarily with Hopfield methods and Kohonen's self-organizing maps, where new results are presented. | ||
| Wednesday November 18, 1998 4:00 in HumB 170 |
Robert Heal Utah State University |
Interactive Web-based Mathematics; An Applet a Day Keeps the Math Doctor Away |
| Abstract: As has been said, mathematics is not a spectator sport. Learning and understanding mathematics well, at any level, requires student engagement. Too much of current instruction fails to actively involve students. There is a remedy; we can now use computers to create web-based virtual manipulatives or concept tutorials, mostly in the form of Java applets that allow students to become dynamically engaged with mathematics. Concepts can be visualized and explored, connections to science applications are just a click away, and the computer in this context is the ultimate patient tutorA wide variety of applets will be presented: Virtual Geoboard, Pentominoes, Ladybug Geometry, Tiling with JavaSketchpad, Triangle Solver, Scatterplot, Modeling with Boxes, 2-D Grapher, and 3-D Grapher. | ||
| Friday October 30, 1998 3:30 in ILB 370 |
Rebekah Valdivia Augsburg College |
The Service Learning Mathematics Practicum of Augsburg College |
| Abstract: The
Mathematics Practicum of Augsburg College is an upper level course in which
students work on service-related mathematical modeling problems. The goal
is to provide community service that utilizes the
mathematical, problem-solving, and abstract reasoning expertise of the
students. This is achieved by soliciting modeling problems from
non-profits and providing the best solutions achievable in a semester's
time. Past community partners include Habitat for Humanity, the Minnesota Aids Project,
and the Superior Wilderness Area Network While working with "real" problems has appeared on the reform platform for some time, the question remains of what constitutes a "real" problem from the student's point of view. The experience of working with a non-profit partner allows students the opportunity to witness the application of mathematics within a human or social context, which translates, in our experience, not only to an increase in appreciation of mathematics, but also an expanded view of its role in our society. |
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| Thursday October 8, 1998 4:00 in ILB 370 3:30 Refreshments |
Dan Nakano Utah State Univ. |
Representation Type of Schur Algebras |
| Abstract: Schur algebras were first introduced by Issai Schur in his doctoral dissertation in 1901. Schur used these finite dimensional algebras to determine the polynomial representations of the complex general linear groups. The representation type of an algebra measures the richness of its representation theory. We completely classify the representation type of Schur algebras. Some have "finite representation type", some are "tame", and some are "wild". | ||
| Past Colloquia |
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Department of Mathematics and Statistics |
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