Past Events

The adjacency matrix A of a graph G is the Hamiltonian for a continuous-time quantum walk on the vertices of G. If u and v are distinct vertices in G, we say perfect state transfer from u to v occurs if there is a time t such that the (u,v)-entry of...

Imagery in M.C. Escher's graphic works not only makes obvious use of geometry, but often provides visual metaphors for abstract mathematical concepts. Again and again Escher strived to capture the concept of infinity. He was also fascinated by and a...

A set $\{a_{1}, a_{2},\ldots, a_{m}\}$ of distinct positive integers is a Diophantine $m$-tuple if the product of any two distinct elements in the set is one less than a square. There is a long history and extensive literature on the study of...

Quadratic form theory started as a part of number theory; people were notably interested in representation questions, such as which number of a given field can be written as a sum of a certain number of squares. In the 1930’s, Witt started the...

Projection operators are fundamental algorithmic operators in Analysis and Optimization. It is well known that these operators are firmly nonexpansive; however, their composition is generally only averaged and no longer firmly nonexpansive. We will...

Given a graph H, say that a graph G is properly rainbow H-saturated if there exists a rainbow H-free proper edge-colouring of G and, for any non-edge e of G, every proper edge-colouring of G+e contains a rainbow copy of H. The proper rainbow...

The action of the automorphisms of a formal group on its deformation space is crucial to understanding periodic families in the homotopy groups of spheres and the unsolved Hecke orbit conjecture for unitary Shimura varieties. We can explicitly pin...

Moses Schonfinkel invented “combinatory logic” — aka combinatory algebra (CA ) — in 1920. It consisted of a binary operation and two constants S and K (called combinators by Haskell Curry who further investigated CAs in the 1950s) which satisfy just...

The prime number theorem (PNT) gives us the density of primes amongst the natural numbers. We can extend this idea to consider whether we have the asymptotic number of primes predicted by the PNT in a given interval. Currently, this has only been...

The design of statistical experiments is a classical topic in statistics, dating back to work of Fisher in the 1930s. One of the mathematical objects used to plan experiments is an "orthogonal array", defined by C. R. Rao. In 1947, Rao proved that...