Bounds for codimensions of fitting ideals

[摘要] We find upper bounds for codimensions of Fitting ideals of a module (over a regular ring), whose symmetric algebra is equidimensional. These bounds are stronger than the classical Eagon-Northcott bounds. Together with lower bounds of Simis and Vasconcelos, they show that the Fitting ideals of a module whose symmetric algebra has an irreducible spectrum can appear only in a finite number of codimensions. Our proof is based on earlier results concerning minimal primes of tensor powers of a symmetric algebra and uses one of the dimension formulae of Huneke and Rossi. (C) 1997 Academic Press.

[发布日期] 1997-08-15