An entropy proof of the Kahn-Lovász theorem

Abstract

Brègman [2], gave a best possible upper bound for the number of perfect matchings in a balanced bipartite graph in terms of its degree sequence. Recently Kahn and Lovász [8] extended Brègman's theorem to general graphs. In this paper, we use entropy methods to give a new proof of the Kahn-Lovász theorem. Our methods build on Radhakrishnan's [9] use of entropy to prove Brègman's theorem.