Hostname: page-component-cd9895bd7-hc48f Total loading time: 0 Render date: 2024-12-23T17:52:35.779Z Has data issue: false hasContentIssue false

On some intermediate rings

Published online by Cambridge University Press:  26 February 2010

Pramod K. Sharma
Affiliation:
School of Mathematics, D.A.V.V., Vigyan Bhawan, Khandwa Road, Indore-452-001, India.
Get access

Extract

Let R be a commutative, Noetherian ring and let Q be the total quotient ring of R. We shall call B an intermediate ring if R ⊂ B ⊂ Q. In [S] it is proved, for an integral domain R, that if R ⊂ B ⊂ Rf where B is flat over R, then B is a finitely generated R-algebra. We observe that the result holds for any commutative, Noetherian ring where f is a non-zero divisor. Our proof [Theorem 1.1] is a little different and straight; it is given for completeness. The idea of the proof in [S] lies in finding an ideal I of R such that IB = B, and for any λ∈I, b∈B there exists m ≥ 1 such that λmb ∈ R. We shall show that even if an intermediate ring B is finitely generated R-algebra, there may not exist any ideal I of R such that IB = B, moreover, if B is not finitely generated R-algebra, we may have IB = B for some ideal I in R.

MSC classification

Type
Research Article
Copyright
Copyright © University College London 1992

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

B-R.Bhatwadekar, S. M. and Roy, A.. Stability theorems for over rings of polynomial rings. Inv. Math., 68, 117127 (1982).CrossRefGoogle Scholar
M.Matsumura, H.. Commutative Ring Theory (Cambridge Univ. Press, 1986).Google Scholar
S.Schenzel, Peter. When is a flat algebra of finite type? Proc. Amer. Math. Soc., 109 (1990).CrossRefGoogle Scholar
G-N-N.Gilmer, R., Nashier, B. and Nicholas, W.. The prime spectra of sub-algebras of affine algebras and their localizations. Pure and Applied Algebra, 57 (1989), 4765.CrossRefGoogle Scholar