Zariski ring
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In commutative algebra, a Zariski ring is a commutative Noetherian topological ring A whose topology is defined by an ideal contained in the Jacobson radical, the intersection of all maximal ideals. They were introduced by Template:Harvs under the name "semi-local ring" which now means something different, and named "Zariski rings" by Template:Harvs. Examples of Zariski rings are noetherian local rings with the topology induced by the maximal ideal, and -adic completions of Noetherian rings.
Let A be a Noetherian topological ring with the topology defined by an ideal . Then the following are equivalent.
- A is a Zariski ring.
- The completion is faithfully flat over A (in general, it is only flat over A).
- Every maximal ideal is closed.