Séminaire Lotharingien de Combinatoire, 93B.77 (2025), 12 pp.

Antoine Abram and Jose Bastidas

The h*-Polynomials of Type C Hypersimplices

Abstract. We study the Ehrhart theory of hypersimplices of type C, as introduced by Lam and Postnikov for general crystallographic root systems. The h*-polynomials of classical hypersimplices are known to relate to various Eulerian statistics on the symmetric group. In this paper, we introduce a new statistic and partial order on signed permutations, which we use to derive explicit formulas for the h*-polynomials of type C hypersimplices. Additionally, we explore connections with other statistics, including flag-excedances and circular descents, flag-descents, and Coxeter descents.


Received: November 15, 2024. Accepted: February 15, 2025. Final version: April 1, 2025.

The following versions are available: