P-Polynomial and Bipartite Coherent Configurations

Abstract

We introduce the notion of P-polynomial coherent configurations and show that they can have at most two fibres. We then introduce a class of two-fibre coherent configurations which have two distinguished bases for the coherent algebra, similar to the Bose-Mesner algebra of an association scheme. Examples of these bipartite coherent configurations include the P-polynomial class of distance-biregular graphs, as well as quasi-symmetric designs and strongly regular designs.

34 pages