Arf good semigroups

摘要

In this paper, we study the property of the Arf good subsemigroups of N-n, with n = 2. We give a way to compute all the Arf semigroups with a given collection of multiplicity branches. We also deal with the problem of determining the Arf closure of a set of vectors and of a good semigroup, extending the concept of characters of an Arf numerical semigroup to Arf good semigroups.