In commutative algebra, a regular ring is a commutative noetherian ring, such that the localization at every prime ideal is a regular local ring: that is, every such localization has the property that the minimal number of generators of its maximal ideal is equal to its Krull dimension.
For regular rings, Krull dimension agrees with global homological dimension.
Jean-Pierre Serre defined a regular ring as a commutative noetherian ring of finite global homological dimension. His definition is stronger than the definition above.
Examples of regular rings include fields (of dimension zero) and Dedekind domains. If A is regular then so is A[X], with dimension one greater than that of A.
Any localization of a regular ring is regular as well.
A regular ring is reduced but need not be an integral domain. For example, the product of two regular integral domains is regular, but not an integral domain.
- since a ring is reduced if and only if its localizations at prime ideals are.
- Is a regular ring a domain
- Tsit-Yuen Lam, Lectures on Modules and Rings, Springer-Verlag, 1999, ISBN 978-1-4612-0525-8. Chap.5.G.
- Jean-Pierre Serre, Local algebra, Springer-Verlag, 2000, ISBN 3-540-66641-9. Chap.IV.D.
- Regular rings at The Stacks Project