English

On some classes of integral domains defined by Krull's $\boldsymbol{a.b.}$ operations

Commutative Algebra 2011-05-18 v1 Algebraic Geometry

Abstract

Let DD be an integral domain with quotient field KK. The bb-operation that associates to each nonzero DD-submodule EE of KK, Eb:={EVVvaluationoverringofD}E^b := \bigcap\{EV \mid V valuation overring of D\}, is a semistar operation that plays an important role in many questions of ring theory (e.g., if II is a nonzero ideal in DD, IbI^b coincides with its integral closure). In a first part of the paper, we study the integral domains that are bb-Noetherian (i.e., such that, for each nonzero ideal II of DD, Ib=JbI^b = J^b for some a finitely generated ideal JJ of DD). For instance, we prove that a bb-Noetherian domain has Noetherian spectrum and, if it is integrally closed, is a Mori domain, but integrally closed Mori domains with Noetherian spectra are not necessarily bb-Noetherian. We also characterize several distinguished classes of bb-Noetherian domains. In a second part of the paper, we study more generally the e.a.b. semistar operation of finite type a\star_a canonically associated to a given semistar operation \star (for instance, the bb-operation is the e.a.b. semistar operation of finite type canonically associated to the identity operation). These operations, introduced and studied by Krull, Jaffard, Gilmer and Halter-Koch, play a very important role in the recent generalizations of the Kronecker function ring. In particular, in the present paper, we classify several classes of integral domains having some of the fundamental operations dd, tt, ww and vv equal to some of the canonically associated e.a.b. operations bb, tat_a, waw_a and vav_a.

Keywords

Cite

@article{arxiv.1105.3319,
  title  = {On some classes of integral domains defined by Krull's $\boldsymbol{a.b.}$ operations},
  author = {Marco Fontana and Giampaolo Picozza},
  journal= {arXiv preprint arXiv:1105.3319},
  year   = {2011}
}