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.
associated graded ring of a regular local ring
Statement
If is regular local of dimension , any cotangent basis induces a graded isomorphism . Conversely, if the associated graded ring of a nonzero Noetherian local ring is isomorphic as a graded -algebra to with standard grading, then is regular of dimension .
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.
associated graded polynomial surjection: Let be nonzero Noetherian local and let lift a basis of . There is a surjective graded -algebra map , determined by , with every variable of degree one.
regular local graded surjection has zero kernel: For the graded map defined by a cotangent basis in a nonzero Noetherian local ring, if , then .
The degree of the Hilbert-Samuel polynomial equals the dimension of the support: Assume the Axiom of Choice. Let be a Noetherian local ring, let be a finite -module, and let be an ideal of definition for . Then the Hilbert-Samuel polynomial has degree
Proof
In a regular local ring the cotangent dimension equals . The polynomial map is surjective and has zero kernel, hence is the claimed isomorphism.
Conversely, the degree-one component of a supplied graded isomorphism has dimension , so . Its cumulative graded dimensions are , also when , where the count is one. These are the lengths of . The Hilbert–Samuel dimension theorem gives , proving regularity.
Depends on
Used by
Dependency tree · two levels
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Sources
- Proposition 25.6, p.67 (standard reference, not scraped)