Generalized Weierstrass semigroups and their Poincaré series.

Abstract

We investigate the structure of the generalized Weierstrass semigroups at several points on a curve defined over a finite field. We present a description of these semigroups that enables us to associate them with combinatorial objects, the Poincaré series and the semigroup polynomial. We show that this Poincaré series determines completely the generalized Weierstrass semigroup and it is entirely determined by the semigroup polynomial. We finish the paper by describing the functional equations occurring to the Poincaré series under the hypothesis of a symmetric generalized Weierstrass semigroup.