Maxmaxflow and Counting Subgraphs

Abstract

We introduce a new graph invariant $\Lambda(G)$ that we call maxmaxflow, and put it in the context of some other well-known graph invariants, notably maximum degree and its relatives. We prove the equivalence of two "dual" definitions of maxmaxflow: one in terms of flows, the other in terms of cocycle bases. We then show how to bound the total number (or more generally, total weight) of various classes of subgraphs of $G$ in terms of either maximum degree or maxmaxflow. Our results are motivated by a conjecture that the modulus of the roots of the chromatic polynomial of $G$ can be bounded above by a function of $\Lambda(G)$.