Past Events

In this talk, we consider colored permutation groups ℤm≀Sn, which contain the symmetric groups Sn≅ℤ1≀Sn and the signed symmetric groups Bn≅ℤ2≀Sn as special cases. Like in Sn, colored permutations in ℤm≀Sn have a notion of cycle type that classifies...

A sign pattern (matrix) has entries in {+, -, 0}. We investigate eigenvalue properties of a sign pattern of order 2n where two of the blocks are prescribed sign patterns of order n, and the other two (order n) blocks are the positive diagonal sign...

For fixed n, consider the symmetric group S_n on the symbols 1,...,n and the set of *star* transpositions, the transpositions that contain the symbol n. A *star factorization* of a permutation b in S_n of length k is the writing of b as the product...

A d-polytope is called (d−i)-simplicial if all of its (d−i)-faces are simplices. It is i-simple if every (d−i−1)-face belongs to exactly i+1 facets. A few low-dimensional examples of (d−i)-simplicial i-simple polytopes arising from regular polytopes...

Local Arthur packets are sets of representations of p-adic groups that help us realize important classes of automorphic forms. They have geometric analogues, called ABV-packets. This was first proposed for p-adic groups by David Vogan following his...

In this talk, we study the performance of some preconditioners for accelerating the convergence of Krylov subspace methods for solving linear systems of equations with a block three-by-three structure. A brief discussion is included regarding how...

In this talk, we study the performance of some preconditioners for accelerating the convergence of Krylov subspace methods for solving linear systems of equations with a block three-by-three structure. A brief discussion is included regarding how...

We study the behavior of h-vectors associated to matroid complexes under weak maps, or inclusions of matroid polytopes. Specifically, we show that the h-vector of the order complex of the lattice of flats of a matroid is component-wise non-increasing...

In this talk I will describe some properties of Meinhardt's model of sidebranching. This is a four-species reaction-diffusion model dating from 1976 describing the interaction of four fields, the concentrations of an activator, an inhibitor, the...

The theory of combinatorial limits, which provides analytic tools to represent and study large discrete structures, resulted in new views on a wide range of topics in mathematics and computer science and also opened new connections between...