Seminars and Colloquia by Series

On the marginals of product measures

Series
Stochastics Seminar
Time
Monday, June 15, 2015 - 14:00 for 1 hour (actually 50 minutes)
Location
Skiles 005
Speaker
Galyna LivshytsKent State University
It was shown by Keith Ball that the maximal section of an n-dimensional cube is \sqrt{2}. We show the analogous sharp bound for a maximal marginal of a product measure with bounded density. We also show an optimal bound for all k-codimensional marginals in this setting, conjectured by Rudelson and Vershynin. This talk is based on the joint work with G. Paouris and P. Pivovarov.

Workshop on Writing a Teaching Philosophy Statement

Series
Professional Development Seminar
Time
Friday, June 12, 2015 - 15:00 for 1 hour (actually 50 minutes)
Location
Skiles 005
Speaker
Helen G. GrundmanBryn Mawr College
A teaching philosophy statement is an crucial part of your dossier. This will be a participatory workshop designed to help you write a statement of your teaching philosophy -- one that accurately reflects your personal beliefs and attitudes. We will begin with some simple exercises to help you identify what you feel is important about teaching in general and your teaching in particular. We will discuss how to translate the outcomes of these exercises into a coherent statement. With luck, there will also be plenty of time for questions. (Please bring paper and something to write with (or a laptop or tablet).)

MCTP REU Seminar

Series
Other Talks
Time
Friday, June 12, 2015 - 11:00 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Dr. Evans HarrellGeorgia Tech
TBA

MCTP REU Seminar

Series
Other Talks
Time
Friday, June 5, 2015 - 11:00 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Martin ShortGeorgia Tech
TBA

Symmetric ideals and numerical primary decomposition

Series
Dissertation Defense
Time
Tuesday, May 26, 2015 - 11:30 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Robert KroneGeorgia Tech
The thesis considers two distinct strategies for algebraic computation with polynomials in high dimension. The first concerns ideals and varieties with symmetry, which often arise in applications from areas such as algebraic statistics and optimization. We explore the commutative algebra properties of such objects, and work towards classifying when symmetric ideals admit finite descriptions including equivariant Gröbner bases and generating sets. Several algorithms are given for computing such descriptions. Specific focus is given to the case of symmetric toric ideals. A second area of research is on problems in numerical algebraic geometry. Numerical algorithms such as homotopy continuation can efficiently compute the approximate solutions of systems of polynomials, but generally have trouble with multiplicity. We develop techniques to compute local information about the scheme structure of an ideal at approximate zeros. This is used to create a hybrid numeric-symbolic algorithm for computing a primary decomposition of the ideal.

Stein Couplings, Log Concavity and Concentration of Measure

Series
Stochastics Seminar
Time
Tuesday, May 19, 2015 - 15:05 for 1 hour (actually 50 minutes)
Location
Skiles 005
Speaker
Umit IslakUniversity of Minnesota
For a nonnegative random variable Y with finite nonzero mean \mu, we say that Y^s has the Y-size bias distribution if E[Yf(Y)] = \mu E[f(Y^s)] for all bounded, measurable f. If Y can be coupled to Y^s having the Y-size bias distribution such that for some constant C we have Y^s \leq Y + C, then Y satisfies a 'Poisson tail' concentration of measure inequality. This yields concentration results for examples including urn occupancy statistics for multinomial allocation models and Germ-Grain models in stochastic geometry, which are members of a class of models with log concave marginals for which size bias couplings may be constructed more generally. Similarly, concentration bounds can be shown when one can construct a bounded zero bias coupling or a Stein pair for a mean zero random variable Y. These latter couplings can be used to demonstrate concentration in Hoeffding's permutation and doubly indexed permutations statistics. The bounds produced, which have their origin in Stein's method, offer improvements over those obtained by using other methods available in the literature. This work is joint with J. Bartroff, S. Ghosh and L. Goldstein.

Combinatorial problems of block transpositions in symmetric groups

Series
Combinatorics Seminar
Time
Tuesday, May 19, 2015 - 13:30 for 1 hour (actually 50 minutes)
Location
Skiles 005
Speaker
Annachiara KorchmarosUniversity of Basilicata
In the study of combinatorial aspects of symmetric groups, a major problem arising from applications to Genetics consists in finding a minimum factorization of any permutation with factors from a given generating set. The difficulty in developing an adequate theory as well as the hardness of the computational complexity may heavily vary depending on the generator set. In this talk, the generating set consists of all block transpositions introduced by Bafna and Pevzner in 1998 for the study of a particular ''genome rearrangement problem''. Results, open problems, and generalizations are discussed in terms of Cayley graphs and their automorphism groups.

On the convergence of Hermite-Pade approximants for rational perturbations of a Nikishin system

Series
Analysis Seminar
Time
Wednesday, May 6, 2015 - 14:00 for 1 hour (actually 50 minutes)
Location
Skiles 005
Speaker
Guillermo LopezUniversity of Madrid Carlos III
In the recent past multiple orthogonal polynomials have attracted great attention. They appear in simultaneous rational approximation, simultaneous quadrature rules, number theory, and more recently in the study of certain random matrix models. These are sequences of polynomials which share orthogonality conditions with respect to a system of measures. A central role in the development of this theory is played by the so called Nikishin systems of measures for which many results of the standard theory of orthogonal polynomials has been extended. In this regard, we present some results on the convergence of type I and type II Hermite-Pade approximation for a class of meromorphic functions obtained by adding vector rational functions with real coefficients to a Nikishin system of functions (the Cauchy transforms of a Nikishin system of measures).

Factorial moments of point processes

Series
Stochastics Seminar
Time
Wednesday, April 29, 2015 - 16:05 for 1 hour (actually 50 minutes)
Location
Skiles 005
Speaker
J.-C. BretonUniversity of Rennes
In this talk, we propose moment identities for point processes. After revisiting the case of Poisson point processes, we propose a direct approach to derive (joint factorial) moment identities for point processes admitting Papangelou intensities. Applications of such identities are given to random transformations of point processes and to their distribution invariance properties.

The dual Steenrod algebra

Series
Geometry Topology Student Seminar
Time
Wednesday, April 29, 2015 - 14:05 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Robert KroneGeorgia Tech

Please Note: For Prof. Wickelgren's Stable Homotopy Theory class

The Steenrod algebra consists of all natural transformations of cohomology over a prime field. I will present work of Milnor showing that the Steenrod algebra also has a natural coalgebra structure and giving an explicit description of the dual algebra.

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