2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/75071Solving a conjecture of M. H. Freedman, L. Lovász and A. Schrijver we prove that a graph parameter is edge reflection positive and multiplicative if and only if it can be represented by an edge coloring model.CombinatoricsMathematical Physics05C99; 82B99text