On curves of Pn with extremal Hartshorne-Rao module in positive degrees

In this paper, we study the curves C in P-n, of degree d and genus g, with extremal Rao function in positive degrees, and non degenerate general hyperplane section. We describe their total ideal and various properties of the generators of the ideal. Moreover, we characterize these curves as intersection of two aCM curves of maximal genus whose union in aCM of maximal genus, and we completely describe the Rao function of these curves in negative degrees, too.