English

Finitely Supported *-Simple Complete Ideals in a Regular Local Ring

Commutative Algebra 2014-01-15 v2

Abstract

Let I be a finitely supported complete m-primary ideal of a regular local ring (R, m). A theorem of Lipman implies that I has a unique factorization as a *-product of special *-simple complete ideals with possibly negative exponents for some of the factors. The existence of negative exponents occurs if the dimension of R is at least 3 because of the existence of finitely supported *-simple ideals that are not special. We consider properties of special *-simple complete ideals such as their Rees valuations and point basis. Let (R, m) be a d-dimensional equicharacterstic regular local ring with m = (x_1, ..., x_d)R. We define monomial quadratic transforms of R and consider transforms and inverse transforms of monomial ideals. For a large class of monomial ideals I that includes complete inverse transforms, we prove that the minimal number of generators of I is completely determined by the order of I. We give necessary and sufficient conditions for the complete inverse transform of a *-product of monomial ideals to be the *-product of the complete inverse transforms of the factors. This yields examples of finitely supported *-simple monomial ideals that are not special. We prove that a finitely supported *-simple monomial ideal with linearly ordered base points is special *-simple.

Keywords

Cite

@article{arxiv.1308.6613,
  title  = {Finitely Supported *-Simple Complete Ideals in a Regular Local Ring},
  author = {William Heinzer and Mee-Kyoung Kim and Matthew Toeniskoetter},
  journal= {arXiv preprint arXiv:1308.6613},
  year   = {2014}
}

Comments

42 pages. To appear in Journal of Algebra

R2 v1 2026-06-22T01:17:40.679Z