3 papers
math.CO2026
The combinatorial Hopf algebra of signed graphs
Jean-Christophe Aval, Raquel Melgar
The theory of combinatorial Hopf algebras is a powerful framework for studying algebraic invariants of combinatorial objects. The aim of this work is to incorporate chromatic invar…
math.CO2025
Chromatic quasisymmetric functions for signed graphs
Jean-Christophe Aval, Raquel Melgar
In 1995, Stanley introduced the chromatic symmetric function of a graph, which specializes to its chromatic polynomial, and which has been the focus of intense research. In 2017, S…
math.AC2024
Poincaré series of semigroups
Antonio Campillo, Raquel Melgar
Many invariants of finitely generated positive cancelative commutative semigroups can be studied from their Poincaré series. We offer and present several closed formulas for them.…