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The Stacks project

Lemma 29.17.3. Let S be a locally Noetherian scheme. The following are equivalent:

  1. S is universally catenary, and

  2. all local rings \mathcal{O}_{S, s} of S are universally catenary.

Proof. Assume that all local rings of S are universally catenary. Let f : X \to S be locally of finite type. We know that X is catenary if and only if \mathcal{O}_{X, x} is catenary for all x \in X. If f(x) = s, then \mathcal{O}_{X, x} is essentially of finite type over \mathcal{O}_{S, s}. Hence \mathcal{O}_{X, x} is catenary by the assumption that \mathcal{O}_{S, s} is universally catenary.

Conversely, assume that S is universally catenary. Let s \in S. We may replace S by an affine open neighbourhood of s by Lemma 29.17.2. Say S = \mathop{\mathrm{Spec}}(R) and s corresponds to the prime ideal \mathfrak p. Any finite type R_{\mathfrak p}-algebra A' is of the form A_{\mathfrak p} for some finite type R-algebra A. By assumption (and Lemma 29.17.2 if you like) the ring A is catenary, and hence A' (a localization of A) is catenary. Thus R_{\mathfrak p} is universally catenary. \square


Comments (2)

Comment #231 by on

The first word of the second paragraph should be Conversely, not Conversly.

Comment #232 by on

Fixed, see here. Also for the other typos you found. Thanks!


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