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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.

Open restrictions of the canonical desingularization

Statement

Assume AC (The Axiom of Choice).

In the setting of Independence of the embedded desingularization from the ambient embedding, let V→U be an open immersion of integral affine K-varieties (Open immersions of schemes) and let res⁡U ⁣:U~→U, res⁡V ⁣:V~→V be the canonical desingularizations. Then there is an open immersion V~↪U~ lifting V→U such that V~→res⁡U−1(V) is an isomorphism over V.

Facts & Assumptions

Given: An open embedding V↪U of affine K-varieties of finite type over a field K of characteristic zero, with canonical desingularizations V~→V and U~→U.

[A1]

The Axiom of Choice: AC is assumed for the canonical-resolution consumer clauses and their cited AC-dependent construction suppliers.

[F1]

Weak embedded desingularization in characteristic zero, Canonical resolutions commute with smooth morphisms: embedded desingularization commutes with smooth ambient morphisms; an open immersion is étale, hence smooth of relative dimension zero.

[F2]

Weak embedded desingularization in characteristic zero, Independence of the embedded desingularization from the ambient embedding: the canonical desingularization of an affine variety is obtained by an embedded desingularization in any smooth affine ambient variety and is independent of that choice.

[F3]

Open immersions of schemes, Locally finite type and finite type morphisms: in the principal case V=Uf for a regular function f; one may choose a closed embedding U↪X into a smooth affine X and a function F on X restricting to f, so that Uf↪XF is a closed immersion and XF↪X is an open immersion of smooth affine schemes.

Proof

1.1A1F1F2F3

The principal case. Assume first V=Uf with f∈K[U]. By [F3] choose a smooth affine ambient X and F∈K[X] with F∣U=f; the open immersions XF↪X and Uf↪U are étale, so [F1] gives a canonical identification of the embedded desingularization of Uf in XF with the restriction of the embedded desingularization of U in X; by [F2] this is the required open embedding of the canonical desingularizations over Uf.

2.1A1F1F2step 1.1∎

The general case. For an arbitrary affine open V↪U, the complement is defined by finitely many functions; covering V by principal opens Ug contained in V and applying step 1.1 to each, the identifications glue because the desingularizations are canonical and their restrictions to the intersections agree by the same argument. This yields an open embedding V~↪U~ lifting V↪U, with V~→res⁡U−1(V) an isomorphism over V.

Depends on

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