How statement and proof provenance work
The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.
- Literature-sourced: the exact statement appears in a cited source; only wording and notation differ.
- AI-adapted: a semantically identical restatement of literature-sourced material, modulo indexing, notation, and boundary cases adopted by the library.
- AI-generated: a genuinely novel statement formulated by AI, with no source for the claim itself.
These labels describe origin, not correctness: citations and verification chips remain separate evidence.
one dimensional regular local rings are dvrs
Statement
A nonzero Noetherian local ring of dimension one is regular if and only if it is a discrete valuation ring. Fields are excluded from the term DVR.
Facts & Assumptions
Given: The objects and hypotheses in the statement. We work with the Axiom of Choice; cited dependent-choice and resolution-existence hypotheses are retained.
regular local domain induction: Every regular local ring is an integral domain.
embedding dimension is minimal maximal ideal generator number: For a nonzero Noetherian local ring , is the least number of generators of .
Equivalent characterizations of a DVR: Let be a nonfield domain. The following are equivalent. 1. is a discrete valuation ring. 2. is a Noetherian valuation ring. 3. is a one-dimensional Noetherian local integrally closed domain. 4. is a local principal ideal domain with nonzero maximal ideal.
The Krull intersection is the -torsion submodule, and it vanishes in the Jacobson-radical case: The first clause below is choice-free; the second uses the published Jacobson-radical unit criterion and therefore inherits its Axiom-of-Choice boundary. Let be a Noetherian commutative ring, let be an ideal, and let be a finite -module. Put Then: 1. is exactly the set of elements for which for some ; 2. if , then .
Proof
If is regular of dimension one, it is a domain and for a nonzero nonunit . Krull intersection gives for any a largest with ; writing , maximality makes a unit.
In a nonzero ideal choose an element with least such exponent . Every other nonzero element has exponent at least , so the ideal is . The zero ideal is principal as well. Thus is a local PID with nonzero maximal ideal, and the stated DVR equivalence applies.
Conversely, a DVR is a nonfield local PID of dimension one. Its maximal ideal is nonzero, and by cancellation in a domain. Therefore its embedding dimension is one and it is regular.
Depends on
Used by
- regular local ring satisfies r one Corollary
- serre normality criterion two directions Corollary
- dvrs as regular local rings Example
- normal domain implies r one Lemma
- polynomial local regularity fibre step Lemma
- serre normality criterion Theorem
Dependency tree · two levels
26 results within two dependency steps of this one, each drawn at its shortest distance from it. An arrow runs from a result to what uses it, so the chart reads left to right and ends at this result, which carries a heavier outline. Every node is a link to that result. Click elsewhere on the chart to enlarge it.
Sources
- Example 12.10, p.116 (standard reference, not scraped)