Other Seminars

May 05, 2009

Ph.D. Thesis Defense - Group Actions on Categorified Bundles

Speaker: Weiwei Pan
Abstract: The term categorification, coined by Louis Crane in 1994, refers to the process of finding analogues of set-theorectic objects in the setting of categories, and, more recently, to the process of finding higher-category analogues of ideas defined in category theory. In application, the concept of categorification often serves to clarify the relationship between existing objects and constructions in mathematics. In this talk we will discuss two particular examples of categorification in algebra and topology - 2-linear representations and 2-vector bundles, as our primarily motivation is to introduce geometrically defined equivariant categorified K-theories. Towards this end, we will define a notion of equivariant 2-bundles, and demonstrate their relation to categorified representations of groups.

May 01, 2009

Ph.D. Thesis Defense - An improved Method for computing Group Cohomology of Congruence Subgroups for SL_3(Z)

Speaker: Becky Hall
Abstract: A well-known theorem due to Manin gives a relationship between modular symbols for a congruence subgroup Γ0(N) of SL2(Z), and the homology of X0(N). A corresponding theorem for congruence subgroups of SL3(Z) was made by Avner Ash. I will discuss an improved method for computing the group cohomology for congruence subgroups of SL3(Z). For W a Γ0(N)-module, I identify the group cohomology of Γ0(N) with a subspace of Wa, for some integer a. This method uses a generalized notion of Grvbner bases in order to determine a minimal generating set for the ideal of conditions describing the desired subspace of Wa

April 27, 2009

Demonstrations of Dynamical Intention for Hybrid Agents

Speaker: Henny Admoni

April 17, 2009

Undergraduate Honors Presentation "On the size of Kakeya sets in finite fields"

Speaker: Matthew Bush
Abstract: A Kakeya set in F^n, where F is a finite field of q elements, is a subset of F^n which contains a line in every direction. In this talk, I will present the result of Zeev Dvir showing that the size of every Kakeya set in F^n is at least C_n q^n, where C_n is a constant depending only on n.

April 17, 2009

Undergraduate Honors Presentation "The unprovability of the continuum hypothesis"

Speaker: Joshua Parks

December 16, 2008

On certain classes of minimally almost periodic groups

Speaker: Franklin R. Gould

October 22, 2008

Finitary isomorphisms of r-processes

Speaker: Stephen Shea, Wesleyan University
Abstract: We will begin by defining r-processes and providing a few examples of this new discrete stationary stochastic process. We will then define finitary isomorphism and review past results in the finitary theory. We will finish with a proof that entropy is a complete finitary isomorphism invariant for finite-state r-processes.

October 11, 2008

2008 Fall Eastern Section Meeting

Two day mathematics meeting with invited addresses by Duong Hong Phong, Columbia University; Monika Ludwig, Polytechnic Inst. of NYU; Pekka Koskela, University of Jyvaskylan; Thomas Warren Scanlon, UC Berkeley. There will also be special sessions with over two hundred speakers.

September 25, 2008

Special Preliminary Examination

Speaker: Glenn Henshaw
Title: Effective results on representations of quadratic forms

May 06, 2008

Representation of definite quadratic forms over F_q[T]

Speaker: Daniel Greengard, Wesleyan University

May 02, 2008

Refined Hunter Searches

Speaker: Jon Keating, Wesleyan University
Abstract: The study of number fields and their properties is a central question of algebraic number theory. We want to determine how requiring number fields to have certain properties will shape the minimal polynomials of elements of those fields. This will allow us to enumerate number fields with these properties by searching for their minimal polynomials. We will begin with a discussion of the work of John Hunter which allows us to bound the coefficients of polynomials associated with number fields that have discriminant less than or equal to a particular value. Then we go on to discuss improvements motivated by the work of Jones and Roberts which allow us to search for polynomials associated with number fields that have a particular discriminant

April 30, 2008

Quasiconformally Homogeneous Domains

Speaker: Anna Rorem, Wesleyan University

April 23, 2008

The Zero Divisor Graph of a Commutative Ring

Speaker: Samantha Gottlieb
Abstract: For a commutative ring R with 1, we let Gamma(R) denote the zero-divisor graph of R. The vertices of Gamma(R) are the nonzero zero-divisors of R, and two distinct vertices x,y are adjacent if and only if xy=0. This talk will discuss several aspects of zero-divisor graphs of finite rings.

April 22, 2008

The word problem for groups

Speaker: Per Stinchcombe, Wesleyan University

April 21, 2008

Polynomial analog of Dirichlet's theorem on primes in arithmetic progressions

Speaker: Daniel Greengard, Wesleyan University

April 17, 2008

A Legendrian Unknotting Move

Speaker: Lauren Alpert
Abstract: For any diagram of a purely topological knot, there exist three moves called Reidemeister moves which preserve the topological structure of the knot. There also exists a 3Delta move2 which does not preserve the structure, but when used finitely many times, can transform the diagram of the knot into a diagram of the unknot. If we impose the constraint y=dz/dx on our knots, we get a class of knots called Legendrian knots. These are typically drawn in the x-z plane (called the front projection). Front projections of Legendrian knots have their own Reidemeister moves, which mostly resemble the Reidemeister moves on topological knot diagrams. We want to construct a Legendrian Delta move by which the front projection of any Legendrian knot can be transformed into the front projection of a Legendrian unknot, while still preserving certain invariants of the original knot.

April 16, 2008

Once-Reinforced Random Walks

Speaker: Rebecca Feiden
Abstract: A simple random walk is a sequence of sums of independent identically distributed random variables. The once-reinforced random walk is a type of edge-reinforced random walk in which edges have two possible weights. If an edge is familiar to the walker it has weight beta and if it is unfamiliar it has weight 1. I will discuss the criteria for recurrence of the once-reinforced random walk on the integers, Z, and the doubly infinite ladder, {Z x {1,2}}.

February 04, 2008

TrackMeNot - Politics Through Technology

Speaker: Helen Nissenbuam, New York University and the Information Law Institute

Abstract: TrackMeNot (TMN) is a Firefox browser extension designed to achieve privacy in web search by obfuscating users' queries within a stream of programatically-generated decoys. TMN protects users against data aggregation and profiling by simulating HTTP search requests with queries extracted from the web. Since August 2006, when the initial version of TMN was made publicly available, free of charge, there have been over 330,000 downloads. The talk will briefly describe how TMN works but will focus mainly on political and ethical values that motivated its design and development. It also addresses some of the criticisms leveled against it.