Patching together a minimal overring. (English) Zbl 1220.13005
Let \(R\) be a commutative integral domain. If \(M\) is a maximal ideal of \(R\) and \(T(M)\) a minimal ring extension of \(R_M\) then \(\{M,T(M)\}\) is called a patching data for \(R\), and \(\{M,T(M)\}\) is said to be patchable if there exists a minimal ring extension \(T\) of \(R\) such that \(T_M\simeq T(M)\) as \(R_M\)-algebras. Further, the domain \(R\) is said to be a patchable domain if every patching data for \(R\) is patchable.
The authors show that any patching data \(\{M,T(M)\}\) for \(R\) is patchable when \(T(M)\) is not a domain, and characterize when a patching data \(\{M,T(M)\}\) for \(R\) is patchable when \(T(M)\) is a domain. Finally, it is proved that in case \(R\) is a Prüfer domain having the property \((\#)\) (this means that \(\bigcap\{R_N\mid N\in A\}\neq\bigcap\{R_N\mid N\in B\}\) for any two distinct nonempty subsets \(A\) and \(B\) of \(\text{Spec}(R)\)), then \(R\) is a patchable domain.
The authors show that any patching data \(\{M,T(M)\}\) for \(R\) is patchable when \(T(M)\) is not a domain, and characterize when a patching data \(\{M,T(M)\}\) for \(R\) is patchable when \(T(M)\) is a domain. Finally, it is proved that in case \(R\) is a Prüfer domain having the property \((\#)\) (this means that \(\bigcap\{R_N\mid N\in A\}\neq\bigcap\{R_N\mid N\in B\}\) for any two distinct nonempty subsets \(A\) and \(B\) of \(\text{Spec}(R)\)), then \(R\) is a patchable domain.
Reviewer: Toma Albu (Bucureşti)
MSC:
13B02 | Extension theory of commutative rings |
13G05 | Integral domains |
13F05 | Dedekind, Prüfer, Krull and Mori rings and their generalizations |
13B21 | Integral dependence in commutative rings; going up, going down |
13C13 | Other special types of modules and ideals in commutative rings |
13C15 | Dimension theory, depth, related commutative rings (catenary, etc.) |