Department of Mathematics - Hill Center, Rutgers University, 110 Frelinghuysen RD, Piscataway, New Jersey 08854-8019
Abstract:
A homological degree of a graded module is an extension of the usual notion of multiplicity tailored to provide a numerical signature for the module even when is not Cohen-Macaulay. We construct a degree, , that behaves well under hyperplane sections and the modding out of elements of finite support. When carried out in a local algebra this degree gives a simulacrum of complexity à la Castelnuovo-Mumford's regularity. Several applications for estimating reduction numbers of ideals and predictions on the outcome of Noether normalizations are given.