The $cl-core$ of an ideal
Abstract
We expand the notion of core to -core for Nakayama closures . In the characteristic setting, when is the tight closure, denoted by *, we give some examples of ideals when the core and the *-core differ. We note that *-core core, if is an ideal in a one-dimensional domain with infinite residue field or if is an ideal generated by a system of parameters in any Noetherian ring. More generally, we show the same result in a Cohen--Macaulay normal local domain with infinite perfect residue field, if the analytic spread, , is equal to the *-spread and is and weakly--residually . This last is dependent on our result that generalizes the notion of general minimal reductions to general minimal *-reductions. We also determine that the *-core of a tightly closed ideal in certain one-dimensional semigroup rings is tightly closed and therefore integrally closed.
Keywords
Cite
@article{arxiv.0810.3033,
title = {The $cl-core$ of an ideal},
author = {Louiza Fouli and Janet Vassilev},
journal= {arXiv preprint arXiv:0810.3033},
year = {2010}
}
Comments
Final version. Math. Proc. Camb. Phil. Soc 149 (2010) 247-262