Seminar

Title: Proof of the monotone column permanent conjecture

Abstract: 

In 1993, Jim Haglund conjectured the following.  If  A  is a  square matrix of real numbers which are weakly decreasing down each column, and J is the all-ones matrix of the same size, then the permanent of the matrix xJ+A is a polynomial with only real roots.

Title:

Abstract:

Differential privacy is about preserving an individuals privacy while maintaining utility in the context of data analysis.

Title: Binary Submatroids

Abstract:

A binary matroid can be thought of as a set of nonzero binary vectors.

Title: Introduction to Monotone Operators

Abstract: 

This talk will be an entry level introduction to the theory of monotone operators as they are presented in Bauschke and Combette’s Convex Analysis and Monotone Operator Theory in Hilbert Spaces.

Title: Recognizing slack matrices

Abstract:

This week, we will be discussing the topic of slack matrices. Slack matrices arise in the context of lifts of polytopes, where, given a polytope P, we can characterize the existence of a lift of P of a given size in terms of properties of an associated slack matrix.

Title: Strongly cospectral vertices in cubelike graphs

Abstract:

A cubelike graph is a Cayley graph of the elementary abelian 2-group. Two vertices in a graph are strongly copsectral if they are cospectral and parallel.

Title: Vertex-minors and sparsity

Abstract:

We discuss an ongoing project with Jim Geelen and Paul Wollan to describe the structure of graph classes excluding a vertex-minor.

Title: Combinatorial Hall algebras

Abstract:

The Hall algebra of a finitary category is an associative (and sometimes Hopf) algebra whose structure constants count the number of extensions between objects.

Title: Linear Programming and Extremal Expanders

Abstract:

Nozaki proved a linear programming bound on the number of vertices that depends on the eigenvalues of a graph.

Title: Excluding an asymmetric group labelled graph

Abstract:

There are several models of group labelled graphs. In the simpler, undirected model, for an abelian group Γ, every edge e receives a label γ(e) in Γ.