Algebra and Combinatorics Seminar
The seminar's organizers for Spring 2017 are
Jens Forsgård,
Julia Plavnik, and
Eric Rowell.

Date Time 
Location  Speaker 
Title – click for abstract 

01/19 3:00pm 
BLOC 628 
Anton Dochtermann Texas State University 
Coparking functions and hvectors of matroids
The hvector of a simplicial complex X is a wellstudied invariant with connections to algebraic aspects of its StanleyReisner ring. When X is the independence complex of a matroid Stanley has conjectured that its hvector is a ‘pure Osequence’, i.e. the degree sequence of a monomial order ideal where all maximal elements have the same degree. The conjecture has inspired a good deal of research and is proven for some classes of matroids, but is open in general. Merino has established the conjecture for the case that X is a cographical matroid by relating the hvector to properties of chipfiring and `Gparking functions' on the underlying graph G. We introduce and study the notion of a ‘coparking’ function on a graph (and more general matroids) inspired by a dual version of chipfiring. As an application we establish Stanley’s conjecture for certain classes of binary matroids that admit a wellbehaved `circuit covering'. Joint work with Kolja Knauer 

01/26 3:00pm 
BLOC 628 
Karina Batistelli U. N. Cordoba 
QHWM of the "orthogonal" and "symplectic" types Lie subalgebras of the matrix quantum pseudodifferential operators
In this talk, we will characterize the irreducible quasifinite highest weight modules of some subalgebras of the Lie algebra of matrix quantum pseudodifferential operators N x N. In order to do this, we will first give a complete description of the antiinvolutions that preserve the principal gradation of the algebra of NxN matrix quantum pseudodifferential operators and we will describe the Lie subalgebras of its minus fixed points. We will obtain, up to conjugation, two families of antiinvolutions that show quite different results when n=N and n 

01/30 4:00pm 
BLOC 220 
Davis Penneys The Ohio State University 
Exotic fusion categories: EH3 exists!
Fusion categories generalize the representation categories
of (quantum) groups, and we think of them as objects which encode
quantum symmetry. All currently known fusion categories fit into 4
families: those coming from groups, those coming from quantum groups,
quadratic categories, and those related to the extended Haagerup (EH)
subfactor. First, I'll explain what I mean by the preceding sentence.
We'll then discuss the extended Haagerup subfactor, along with the
newly constructed EH3 fusion category (in joint work with Grossman,
Izumi, Morrison, Peters, and Snyder), and the possibility of the
existence of EH4. 

02/23 3:00pm 
BLOC 628 
Ka Ho Wong Chinese University of Hong Kong 
TBA 

03/23 3:00pm 
BLOC 628 
Dimitar Grantcharov UT Arlington 
TBA 

03/30 3:00pm 
BLOC 628 
Cris Negron MIT 
TBA 

04/13 3:00pm 
BLOC 628 
Sarah Witherspoon & Catherine Yan 
Algebra and Combinatorics Spring 2019 Course Discussion. 
Archives