Past Events

Abstract: A k-list-assignment for a graph G is a function L from V(G) to the set of subsets of {1,…,k}. The list-k-colouring problem asks, given G and a k-list-assignment L, is there a colouring f of G with f(v) in L(v) for all v in V(G)? This...

Abstract: In 1964, Kemperman proved the following continuous nonabelian counterpart of the Cauchy-Davenport theorem: If G is a connected unimodular locally compact group with a left (and hence right) Haar measure \mu, A, B \subseteq G are nonempty...

Here I give two tiny talks on some of my research from the past couple years. In the first half of the talk I re-examine some popular heuristics for epidemic "time of spread" through the world airline network, and use hitting times and branching...

Abstract: From a group action on a space, define a variant of the configuration space by insisting that no two points inhabit the same orbit. When the action is almost free, this "orbit configuration space" is the complement of an arrangement of...

Abstract: Given a group G with a finite set of generators, S, it is natural to ask if the product of n generators from S evaluate to the identity. The enumerative version of this problem, known as the cogrowth problem, counts the number of such...

Understanding how cells change their identity and behaviour over time in living systems is a key question in many fields of biology. Measurement of cell states is inherently destructive, and so the relationship of the current state of a cell to some...

Abstract: We will start with an introduction to webs, standard Young tableau promotion, and the relationship between web rotation and tableau promotion. We will then discuss increasing tableaux---a K-theoretic analogue of SYT---and K-promotion. A big...

Abstract: The problem of maximizing nonnegative monotone submodular functions under a certain constraint has been intensively studied in the last decade, and a wide range of efficient approximation algorithms have been developed for this problem...

Abstract: The Green's functions of a graph are the pseudo inverses of the Laplacians and therefore are useful for solving many types of Laplace equations in discrete settings.In this talk, we will give combinatorial interpretations of Green's...

Entropic optimal transport has received a lot of attention in recent years and has become a popular framework for computational optimal transport thanks to the Sinkhorn scaling algorithm. In this talk, I will discuss the multi-marginal case which...