Simon Fraser University

The dimension of a poset P is the minimum number of total orders whose intersection is P. We prove that the dimension of every poset whose comparability graph has maximum degree $\Delta$ is at most $\Delta log^{1+o(1)} \Delta$. This result improves...

The celebrated Erdős-Pósa theorem states that every undirected graph that does not admit a family of k vertex-disjoint cycles contains a feedback vertex set (a set of vertices hitting all cycles in the graph) of size O(k log k). After being known for...

Results on a two way convection-diffusion problem; an asymptotic error analysis on a piece-wise uniform grid; and a framework for understanding quadrature errors in Finite Element Methods are presented. These results were never published, although I...

The talk starts with a short survey on a mathematical game known as Racetrack, in which a vehicle moves in discrete rounds and can slightly modify its movement vector every round. The goal is to minimize the amount of rounds needed to attain some...

A function $f:\F_2^n\to \F_2^n$ is called almost perfect nonlinear (APN) if $f(x) + f(y) + f(z) + f(x + y + z)= 0$ all $x,y,z$ such that $|\{x,y,z,x+y+z\}|=4$.. The motivation to study these functions comes from cryptography, since the defining...

Let G=(V,E) be an undirected graph on n vertices and λ:E →2^N a mapping that assigns to every edge a non-empty set of positive integer labels. These labels can be seen as discrete times when the edge is present. Such a labeled graph G'=(G,λ) is said...

What is a game? Mathematically speaking, a game has players, strategies and scores to explain why the players win or lose. Games which are modelled with differential equations are called differential games. Common examples are pursuit-evasion games...

Integer programming is one of the most fundamental problems in discrete optimization. While integer programming is computationally hard in general, there exist efficient algorithms for special instances. In particular, integer programming is fixed...

In this talk I will introduce a new semi-algebraic proof system, called Stabbing Planes that is in the style of DPLL-based modern SAT solvers. Stabbing Planes proofs extend the DPLL branching from single variables to branching on arbitrary linear...