Syzygies of GS monomial curves and Weierstrass property.

We find a resolution for the coordinate ring R of an algebraic monomial curve associated to a G numerical semigroup (i.e. generated by a generalized arithmetic sequence), by extending a previous paper (Gimenez, Sengupta, Srinivasan) on arithmetic sequences . A consequence is the determinantal description of the first syzygy module of R. By this fact, via suitable deformations of the defining matrices, we can prove the smoothability of the curves associated to a large class of semigroups generated by arithmetic sequences, that is the Weierstrass property for such semigroups.