Seminar

Title: Partial progress on enumerating K₅ descendants

Abstract:

We call a particular operation on a graph which converts one triangle into two triangles a double triangle expansion, and call all those graphs which can be obtained from repeated double triangle expansions of a fixed graph the double triangle descendants of the graph.

Title: Spanning cycles in Hypergraphs

*Please note the room change from the previous week

Abstract:

A long time ago, Lehel asked whether the vertex set of every complete graph, whose edges have been coloured red and blue, can be partitioned into a red and a blue cycle.

Title: Stochastic optimization methods beyond stochastic gradient descent

Abstract:

We will present a very general framework for unconstrained stochastic optimization which encompasses standard frameworks such as line search and trust region using random models.

Title: Stable Matching Overview

Abstract:

This semester, the CombOpt Reading Group studies Stable Matching. In this talk we will introduce the basic concepts in stable matching, provide an overview of the planned papers to be discussed this semester, and mention interesting open questions along the way.

Title: The Erdős-Pósa property for A-paths

Abstract:

Let A be a set of vertices in a graph G. An A-path is a path whose ends are in A. Gallai proved, for any integer k, that there are either k disjoint A-paths or there is a set of at most 2k vertices that hit all A-paths.

Title: Deducing Kurdyka-Łojasiewicz exponent of optimization models

Abstract:

Kurdyka-Łojasiewicz (KL) exponent is an important quantity for determining the qualitative convergence behavior of many first-order methods.

Title: From Warragul to Waterloo

Abstract:

As Tom Lehrer once said “Some of you may have run into mathematicians, and therefore had occasion to wonder how they got that way”; this talk will be a partial explanation of how I got this way.

Title: Recovery of a mixture of Gaussians by sum-of-norms clustering

Abstract:

Sum-of-norms clustering is a method for assigning n points in R^d to K clusters, 1 ≤ K ≤ n, using convex optimization.

Title: Graph Sparsification by Effective Resistances

Abstract:

We will discuss an application of the matrix concentration inequalities of Tropp to spectral sparsification of graphs.

Title: Erdös-Rényi Graphs

Abstract:

These might not be the Erdös-Rényi graphs you first thought of. Let V be a 3-dimensional vector space over a field of odd order q.