English

Quasi-valuations and algebras over valuation domains

Rings and Algebras 2013-08-23 v1

Abstract

Suppose FF is a field with valuation vv and valuation domain OvO_{v}, and RR is an OvO_{v}-algebra. We prove that RR satisfies SGB (strong going between) over OvO_{v}. We give a necessary and sufficient condition for RR to satisfy LO (lying over) over OvO_{v}. Using the filter \qv constructed in [Sa1], we show that if RR is torsion-free over OvO_{v} then RR satisfies GD (going down) over OvO_{v}. In particular, if RR is torsion-free and (R×Ov)Ov×(R^{\times} \cap O_{v}) \subseteq O_{v}^{\times}, then for any chain in Spec(Ov)\text{Spec}(O_v) there exists a chain in Spec(R)\text{Spec}(R) covering it. Assuming RR is torsion-free over OvO_{v} and [ROvF:F]<[R \otimes_{O_{v}}F:F]< \infty, we prove that RR satisfies INC (incomparabilty) over OvO_{v}. Assuming in addition that (R×Ov)Ov×(R^{\times} \cap O_{v}) \subseteq O_{v}^{\times}, we deduce that RR and OvO_{v} have the same Krull dimension and a bound on the size of the prime spectrum of RR is given. Under certain assumptions on RR and a \qv defined on it, we prove that the \qv ring satisfies GU (going up) over OvO_{v}. Combining these five properties together, we deduce that any maximal chain of prime ideals of the \qv ring is lying over Spec(Ov)\text{Spec}(O_{v}), in a one-to-one correspondence.

Keywords

Cite

@article{arxiv.1308.4743,
  title  = {Quasi-valuations and algebras over valuation domains},
  author = {Shai Sarussi},
  journal= {arXiv preprint arXiv:1308.4743},
  year   = {2013}
}

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27 pages