The genus of a quotient of several types of numerical semigroups

Abstract

Finding the Frobenius number and the genus of any numerical semigroup [Formula: see text] is a well-known open problem. Similarly, it has been studied how to express the Frobenius number and the genus of a quotient of a numerical semigroup. In this paper, by enumerating the Hilbert series of each type of numerical semigroup, we show an expression for the genus of a quotient of numerical semigroups generated by one of the following series: arithmetic progression, geometric series, and Pythagorean triple.