Prime T-Ideals in Polynomial and Power Series Rings Over a Pseudo-Valuation Domain

Let R be an m-dimensional pseudo-valuation domain with residue field k, let V be the associated valuation domain with residue field K, and let k ₀ be the maximal separable extension of k in K. We compute the t-dimension of polynomial and power series rings over R. It is easy to see that t-dim R[x ₁,…, x _n ] = 2 if m = 1 and K is transcendental over k, but equals m otherwise, and that t-dim R[[x ₁,…, x _n ]] = ∞ if R is a nonSFT-ring. When R is an SFT-ring, we also show that: (1) t-dim R[[x]] = m; (2) t-dim R[[x ₁,…, x _n ]] = 2m ? 1, if n ≥ 2, K has finite exponent over k ₀, and [k ₀: k] < ∞; (3) t-dim R[[x ₁,…, x _n ]] = 2m, otherwise.     

A Note on t-SFT-rings

We define a nonzero ideal A of an integral domain R to be a t-SFT-ideal if there exist a finitely generated ideal B ? A and a positive integer k such that a ^k  ? B _v for each a ? A _t , and a domain R to be a t-SFT-ring if each nonzero ideal of R is a t-SFT-ideal. This article presents a number of basic properties and stability results for t-SFT-rings. We show that an integral domain R is a Krull domain if and only if R is a completely integrally closed t-SFT-ring; for an integrally closed domain R, R is a t-SFT-ring if and only if R[X] is a t-SFT-ring; if R is a t-SFT-domain, then t ? dim R[[X]] ≥ t ? dim R. We also give an example of a t-SFT Prüfer v-multiplication domain R such that t ? dim R[[X]] > t ? dim R.     

On t-Dimension over Strong Mori Domains

In this note we prove that if R is a strong Mori domain with t-dim R = n and with countably many prime v-ideals, then there is a chain of rings between R and R^w R1=R belong to R2……belong to Rn lohtuin in R^w such that each R, is also a strong Mori domain and t-dim Rk=n - k ＋ 1 for k = 1,2,..., n.