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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.

A point and projective-line check of source-first convolution and opposite composition

Example

Assume the Axiom of Choice as inherited from the cited constructible and cellular suppliers. In the point/projective-line geometry with E=pt, X1=pt, X2=P1, d1=0, d2=1 and L1=k, L2=RΓ(P1,k)[1] in the setting of Equivariant Borel–Moore homology and oriented correspondence convolution, let α∈Ext⁡−1(L1,L2) be the unit k→RΓ(P1,k) and let β∈Ext⁡1(L2,L1) be point evaluation RΓ(P1,k)[1]→k[1], that is, evaluation H0(P1,k)→k shifted by 1 and extended by zero on H2. Then α∗β=β[−1]∘α=id⁡k in the source-first convention of Equivariant Borel–Moore homology and oriented correspondence convolution, and under the correspondence isomorphism of Proper-pushforward Ext is equivariant Borel–Moore homology of the fiber product one has [P1]∗[pt]=[pt]: the refined diagonal intersection of the fundamental class of P1 with the point class is the point class, and proper pushforward to the point corner gives its generator.

Facts & Assumptions

Given: the Axiom of Choice; the trivial group G=1; the base E=pt; the sources X1=pt and X2=P1 with d1=0, d2=1; the proper maps f1:pt→pt and f2:P1→pt; the objects L1=k and L2=RΓ(P1,k)[1]; the unit α:k→RΓ(P1,k) and the evaluation β:RΓ(P1,k)[1]→k[1]; and the conventions of Equivariant Borel–Moore homology and oriented correspondence convolution.

[F1]

Proper-pushforward Ext is equivariant Borel–Moore homology of the fiber product supplies natural isomorphisms Φijr:Hom⁡(Li,Lj[r])→∼Hdi+dj−rBM,G(Zij;k) for all r and (i,j), and Equivariant Borel–Moore homology and oriented correspondence convolution fixes the source-first product a∗b=h∗ΔXj!(a⊠b) with degree drop 2dj, the corner degrees and the normalized diagonal class.

[F2]

Verdier-duality identification intertwines Yoneda product and oriented convolution supplies Φikr+s(β[r]∘α)=Φijr(α)∗Φjks(β) for composable morphisms, with the identity mapped to [ΔXi].

[F3]

The projective line P1 is smooth of complex dimension 1 (Complex projective space and its holomorphic charts) and proper over Spec⁡C (Finite-dimensional projective space is proper over every base); under P1=Gr⁡1(C2) the Schubert cells of Stiefel spaces, Grassmannians, and tautological bundles, Schubert cells in real and complex Grassmannians and Schubert cells give the stable Grassmannian CW structure give a finite CW structure with one cell in real dimension 0 and one in real dimension 2.

[F4]

With no cells in adjacent dimensions every cellular differential vanishes and Hn≅Cncell (A CW complex with no cells in adjacent dimensions has zero cellular boundary), and cellular cochains compute cohomology with local coefficients (Cellular cochains compute cohomology with local coefficients).

[F5]

Complex-oriented diagonal Thom classes realize exceptional exchange on supports fixes the positive complex orientation and the normalization of the diagonal Thom intersection: the positive generator is the one evaluating to +1 on positively oriented normal fibers, and the refined operation is independent of transversality.

[F6]

Under AC, constant-sheaf cohomology on a metric space with a contractible-open neighborhood basis equals singular cohomology (Locally contractible metric spaces have singular constant sheaf cohomology). The projective-line charts and its Hermitian-projector embedding in [F3] supply those hypotheses.

[A1]

The Axiom of Choice is inherited through the cited constructible and cellular suppliers; the explicit finite computations below are choice-free (The Axiom of Choice).

Verification

technique · direct
1.1F3F4F6algebra

The geometry and the cohomology of the projective line. The fiber products are Z12=Z21=P1. By [F3] its Schubert CW structure has one 0-cell and one 2-cell, so the cellular cochain complex is k⊕k[−2]. By [F4] it computes singular cohomology, and [F6] identifies this with constant-sheaf cohomology. Choosing cocycles representing the two generators gives a quasi-isomorphism k⊕k[−2]→RΓ(P1,k). Hence L2≃k[1]⊕k[−1] and L1=k.

2.1step 1.1algebra

The two classes and their composites. The unit α:k→RΓ(P1,k) includes the degree-zero summand, generating Ext⁡−1(L1,L2)=k. Evaluation at a point projects to that summand; its shift β:L2→k[1] generates Ext⁡1(L2,L1)=k, since Hom⁡(k[−2],k)=0. Therefore β[−1]∘α=id⁡k. The reverse composite α[1]∘β is also nonzero: it is the projector of L2=k[1]⊕k[−1] onto k[1], and is neither zero nor id⁡L2.

3.1F1F2step 1.1step 2.1

The convolution check. Apply [F2] with (i,j,k)=(1,2,1) and degrees r=−1, s=1 to the composable pair α:L1→L2[r] and β:L2→L1[s]: since β[r]∘α=β[−1]∘α=id⁡k by step 2.1, the product theorem gives Φ110(id⁡k)=Φ12−1(α)∗Φ211(β), so α∗β=id⁡k in the source-first convention, and the right-hand side is the convolution product of [F1]. The corner degrees are d1+d2−r=2 for α and d2+d1−s=0 for β.

4.1A1F1F2F5step 2.1step 3.1∎

The geometric product. The adjunction chain of [F1] sends α to id⁡kP1, hence to the positive fundamental class [P1]. Write i:pt↪P1 for the evaluation point. Evaluation is the global-sections image of kP1→i∗k, and its adjoint under RΓ⊣a!, a:P1→pt, is the composite kP1→i∗k=i∗i!ωP1→ωP1, with the last arrow the proper trace. Thus Φ211(β)=i∗[pt] with coefficient +1. Geometrically P1×{i} meets the middle diagonal of P1×P1 transversely at (i,i); the map from its tangent line to the complex normal line of the diagonal is an isomorphism, preserving the real orientation. The positive Thom cap of [F5] therefore gives that point with multiplicity +1, and proper pushforward to Z11=pt gives [pt]. This computes [P1]∗[pt]=[pt], with middle degree drop 2 and no permutation sign, agreeing with step 3.1. It verifies a transverse instance of the calculus, not its general nontransverse case. AC is inherited through [A1].

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