Events

Unique Vector Colorings: Core Concepts

Abstract: 

A vector $k$-coloring of a graph G is an assignment of real unit vectors to the vertices of $G$ such that vectors assigned to adjacent vertices have inner product at most $-1/(k-1)$.

Algorithms for Random k-SAT and Colouring Random Graphs

Abstract:

Random instances of k-SAT have long been recognized as being very challenging to solve algorithmically. Random graphs are also very difficult to colour.

The Laplacian Spectral Excess Theorem for Distance-regular Graphs

Abstract: 

The spectral excess theorem states that, in a regular graph $G$, the average excess, which is the mean of the numbers of vertices at maximum distance from a vertex, is bounded above by the spectral excess (a n

Properties of Graphs With Bounded Highway Dimension

Abstract: 

The "highway dimension" (hd) of a graph was defined by Abraham et al. in 2010, in order to model transportation networks. In particular, a road network can be modelled as a graph with bounded hd.

A Sampler of Combinatorial Problems on Spheres

Abstract: 

In my first month as a graduate student at the University of Waterloo, I somehow selected an advisor (and that is a story entirely of its own) and asked him to give me a paper to read.

A conference to celebrate the work of Chris Godsil

Conference poster (PDF).

Banquet photographs.

The Erdos-Ko-Rado Theorem, An Algebraic Perspective

Abstract: 

Several years ago I had the good fortune to have an extremely
productive post-doctoral fellowship with Chris. Our work from this

Packing and Covering Small Cliques

Abstract: 

A long-standing conjecture of Zsolt Tuza states that if a graph contains at most k pairwise edge-disjoint triangles, then it also contains a set of at most 2k edges whose deletion creates a triangle free graph.

Recent Advances in Algorithms For The Discrete Logarithm Problem

Abstract: 

Beginning in February 2013, several teams of researchers announced dramatic breakthroughs in algorithms for computing discrete logarithms in small characteristic finite fields, culminating in a quasi-polynomial algorithm.

Highly Connected Matroids in Minor-closed Classes

Abstract:

With Bert Gerards and Geoff Whittle we have a structural
characterization of the matroids in any minor-closed class over any given