## Lethbridge Number Theory and Combinatorics Seminar: Steve Wilson

- Date: 03/12/2018

University of Lethbridge

The BGCG Construction

Well, it's not really a construction yet -- it's more like a template for constructions.

It's a way to take many copies of one tetravalent graph B, the 'base graph', and identify each edge-midpoint with one other according to another graph C, the 'connection graph' to produce a bipartite tetravalent graph. If the identifying is done with caution, wisdom and, um, insouciance, the resulting graph will have lots of symmetry.

The cunning of the identifications is related to edge-colorings of the base graph which are themselves nicely symmetric, and we will give several examples where the symmetry can actually be achieved.

**Time:** 12:00-12:50pm

**Location:** B543 University Hall