Discrete mathematics seminar - Edge-biregular maps of every feasible type exist

Dates

Wednesday, May 25, 2022 - 14:00 to 15:00

Speaker: Olivia Jeans (The Open University)

Abstract:

An edge-biregular map is a highly symmetric map with an automorphism group which partitions the flag set of the map into two orbits in such a way that the action is not edge-transitive. Such maps necessarily have even valency and even face length, and are equivalent to groups generated by two pairs of commuting involutions. In this talk we will use permutation diagrams to prove that edge-biregular maps exist for every type (2k,2l), focussing especially on those whose underlying group is alternating or symmetric.