Events

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: 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: 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: The 600-cell

Abstract:

If d ≥ 5, then in R^d there are exactly three regular polytopes (simple, hypercube, dual hypercube). If d = 3 we have the icosahedron and the dodecahedron in addition. If d = 4, there are again two exceptional regular polytopes, the so-called 120-cell and 600-cell.

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: 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: 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: The 600-cell as a Cayley graph

Abstract:

I will discuss some of the things we can learn about the 600-cell by viewing it as a Cayley graph for the group SL(2,5) (once I've discussed the basic properties of this group).

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: A Fixed-Point Approach to Stable Matchings

Abstract:

We describe a xed-point based approach to the theory of bipartite stable matchings.