Alphabeta Math
LemmaStatement: AI-generatedProof: AI-generated
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.

The identified support fiber is the classical relative Hom before Gysin

PDF p. 7: Lemma2.9: smooth-point supported purity

Statement

Assume the Axiom of Choice and the completed site and universe bounds of the supplied point-support and classical derived-category constructions. For j≥0, the actual point-supported cohomology on V is Hi(Cj,x(V))≅Hom⁡DMNiseff,−(cofib⁡(M(V∖x)→M(V)),Z(j)[i]). Here the relative motive is the image of the cone of the actual open-immersion map of transfer-representable complexes. The smooth-pair Gysin input applies to this exact first arrow and identifies its cofiber with M(Spec⁡L)(d)[2d]. For j≥d, the preceding coefficient cancellation therefore computes the group as Hmoti−2d,j−d(L,Z). No Gysin statement for singular closed subschemes or an independently chosen quotient evaluation is used.

Facts & Assumptions

Given: The actual smooth finite-type pair, its identified restriction arrow, j≥0, the Axiom of Choice, and the completed site and universe bounds.

Goal: Supply the exact classical relative-object interpretation before applying the imported Gysin triangle.

[A1]

The Axiom of Choice is inherited from the neighbourhood and actual-support constructions in [F1]–[F2], the source contract of the classical derived-category input in [F1], and the coefficient comparison in [F3]. It is used when those supplied constructions are invoked; the Hom/fiber and shift calculations add no further choice. The Axiom of Choice

[F1]

The actual smooth restriction arrow gives the point-supported cycle fiber supplies an equivalence of actual EM and classical restriction diagrams. External classical coefficient, derived Yoneda and effective-localization interface supplies the natural derived Yoneda model and the A¹-local target interpretation.

[F2]

Gysin purity for a smooth closed pair supplies the Gysin cofiber for this perfect-field smooth separated finite-type pair. A smooth point has the exact finite-type excision pair verifies both smoothness conditions and pure codimension.

[F3]

Perfect-field cancellation removes exactly d coefficient twists supplies the precise coefficient comparison for j≥d. Support fibers with explicit cohomological indexing fixes the actual fiber convention.

Proof

1.1A1F1

In the derived category of Nisnevich sheaves with transfers, let f:Ztr(V∖x)→Ztr(V) be the actual map and let D=cone⁡(f). Resolve the A¹-local coefficient by the derived-Hom model in [F1]. Yoneda evaluation on that resolution makes the two Hom complexes exactly the classical values on V and V∖x, with the actual restriction between them. Applying Hom to the ordinary cone identifies RHom⁡(D,Z(j)) with the fiber of that arrow. By [F1], this is the already identified EM support fiber. Taking cohomology, A¹-locality of the target identifies these derived Hom groups with the displayed groups in DM, by the localization property in [F1]. No unrelated objectwise equivalences have entered this construction.

2.1A1F2F3step 1.1∎

In DM, the image of D is a cofiber of M(V∖x)→M(V), the same first arrow as in [F2]. Its Gysin cofiber is therefore compatibly isomorphic to M(Spec⁡L)(d)[2d]; no uniqueness of cone is asserted from the triangulated axioms alone. Substitute this isomorphism in step 1.1. For j≥d, apply [F3] to obtain exactly the stated residue-field group. This proves the Gysin/coefficient route for the actual support fiber, with its full scope checked before use.

Depends on

Used by · 1

Dependency tree · 3 levels

Arrows run from prerequisites to the items that use them. External source nodes link directly to the cited text. The view shows up to three dependency steps; open a prerequisite to continue.