Layered resolutions of Cohen–Macaulay modules

Abstract

Let S be a Gorenstein local ring and suppose that M is a finitely generated Cohen-Macaulay S-module of codimension c. Given a regular sequence f1, . . . , fc in the annihilator of M we set R = S/(f1, . . . , fc) and construct layered S-free and R-free resolutions of M . The construction inductively reduces the problem to the case of a Cohen-Macaulay module of codimension c 1 and leads to the inductive construction of a higher matrix factorization for M . In the case where M is a su ciently high R-syzygy of some module of finite projective dimension over S, the layered resolutions are minimal and coincide with the resolutions defined from higher matrix factorizations we described in [EP].