collaborators

8 papers

math.CO2026

Unimodality shenanigans in Ehrhart theory

Luis Ferroni

We show the existence of counterexamples to a four-decade-old conjecture attributed to Stanley concerning the unimodality of -polynomials of IDP polytopes. As additional appli…

math.CO2026

Almost factorial many facets for 0/1-polytopes

Federico Castillo, Luis Ferroni

A long-standing question posed by Fukuda (1995) and Ziegler (2000) inquires about the asymptotic behavior of , the maximum number of facets that an -dimensional -poly…

math.CO2026

Symmetric edge polytopes are not gamma-positive

Luis Ferroni

A conjecture posed by Ohsugi and Tsuchiya (2019) postulates that the Ehrhart -polynomials of symmetric edge polytopes are -positive. We disprove this conjecture by exhibiti…

math.CO2026

Ehrhart positivity for lattice path matroids

Luis Ferroni, Alejandro H. Morales, Greta Panova

We prove that all lattice path matroids are Ehrhart positive. This unifies and generalizes numerous results on the Ehrhart positivity of matroids developed over the last two decade…

math.CO2026

Luck and magic for Pitman-Stanley polytopes and parking functions

Nicolas Avila, Luis Ferroni, Alejandro H. Morales

Motivated by the combinatorics of parking functions and their several generalizations, we study the Ehrhart theory of Pitman--Stanley polytopes. We prove a strong positivity phenom…

math.CO2025

Eulerian posets and -polynomials

Luis Ferroni, Roberto Riccardi

Let be a finite partially ordered set. In a recent series of works, Proudfoot introduced the notion of -polynomials associated with -kernels, providing a unified framewor…

math.CO2025

Skew shapes, Ehrhart positivity and beyond

Luis Ferroni, Alejandro H. Morales, Greta Panova

A classical result by Kreweras (1965) allows one to compute the number of plane partitions of a given skew shape and bounded parts as certain determinants. We prove that these dete…

math.CO2025

Preservation of log-concavity on gamma polynomials

Luis Ferroni, Greta Panova, Lorenzo Venturello

Every symmetric polynomial with center of symmetry can be expressed as a linear combination in the basis . The -polynomial of , which we deno…