This week's seminar is given by our own Sabrina Lato, Umeå universitet.
Title: Distance-Biregular Graphs
Abstract: Distance-biregular graphs were introduced by Delorme as an extension of distance-regular graphs. Distance-biregular graphs can also be motivated as a class of bipartite graphs generalizing the structure of graphs that meet a bipartite Moore bound. In this talk, we discuss a spectral version of that bound and show the extremal examples meeting the bipartite spectral Moore bound are distance-biregular. Interesting families of distance-biregular graphs come from design theory and finite geometry, and in this talk we also discuss some of those families, as well as directions to take to find new constructions.
