TITLE: Counting vertices and cubes in Buneman graphs (or median graphs)
SPEAKER: Youngbin Choe (Pohang University of Science and Technology)
DATE: March 17, 2006
TIME: 01 : 00 PM
ROOM: HP 4369, Carleton University
ABSTRACT: This talk is about some combinatorial problems that arose in the study of phylogenetics. Buneman introduced a special graph called a Buneman graph to prove Splits-Equivalence Theorem by defining the vertices and edges in a particular way. As a natural generalization of trees and hypercubes, Buneman graphs have close connection to the study of evolutionary relationships within populations. In general, it is not easy to compute the number of vertices and the number of maximal subcubes of a Buneman graph, which are two simple measures of complexity of a given graph. In this talk I will present a special family of Buneman graphs and show a combinatorial way for computing these measures. This is joint work with K.T.Huber, J.H.Koolen, Y.S.Kwon, and V.Moulton.