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RemarkRemark: Literature-sourcedProof: Not applicablePipeline-generatedjudge pass (gpt-6-luna)
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.

Toën, Kapranov, and unweighted triangle counts are distinct constructions

Remarks

Toën's DH(T) is built from isomorphism classes of perfect modules in a dg-enhancement. Its coefficient counts homotopy-cofiber arrows and includes the alternating higher-Ext factor of Toën derived Hall numbers have the higher-Ext orbit formula. The dg enhancement is essential: an unweighted count of triangle orbits is not the same coefficient; the finite-vector-space calculation on the companion examples page illustrates the missing higher-homotopy factor.

Kapranov's lattice Hall algebra for a finitary hereditary category has generators indexed by shifts of heart objects and additional group-algebra generators kα indexed by α∈K0(A), the group generated by object classes modulo short-exact-sequence relations. Its lattice and K0 data are part of its definition. Toën's derived Hall algebra instead has a basis indexed by perfect derived objects and uses homotopy weights. These are distinct constructions; this remark makes no claim that the resulting algebras are non-isomorphic or that one embeds in the other. Schiffmann's §5.6 displays both presentations and explicitly says they are closely related but not equivalent constructions.

Motivic Hall products use stack functions and a chosen motivic coefficient theory; cohomological Hall products use equivariant cohomology correspondences and their grading/push-pull data. Their examples and hypotheses belong to the separate pages motivic-hall-algebras-and-integration and cohomological-hall-algebras-and-quiver-correspondences. They are not consequences of the Toën product defined here.

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