Gary MacGillivray

A 1935 problem of Erdos and Szekeres asks for the smallest number, r(n), such that given any collection of r(n) points in the plane there exist n points no 3 of which are the vertices of a right triangle. It is known that r(4) = 8, 9, or 10, and in...

An (m, n)-mixed graph consists of a set of vertices, any two of which may be joined by either an edge of one of m colours or an arc of one of n colours, or not be joined at all. The operation of switching at a vertex v of an (m, n)-mixed graph with...

The main objective of PDMW is to bring together researchers in discrete mathematics in the prairie region (Manitoba, Saskatchewan and Alberta), as well as neighbouring provinces and states, with the goal of providing opportunities for networking and...