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TheoremStatement: Literature-sourcedProof: AI-generatedPipeline-generatedprecheck passjudge pass (gpt-5.6-terra)audited 2026-09-01
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 long exact sequence in homology

Statement

Let 0→A∙→B∙→C∙→0 be a short exact sequence of complexes in an abelian category. Then there is an exact sequence ⋯→Hn(A)→Hn(B)→Hn(C)→∂nHn−1(A)→Hn−1(B)→Hn−1(C)→⋯ .

Facts & Assumptions

Given: A short exact sequence 0→A∙→B∙→C∙→0 of complexes.

[L1]

Every chain map induces a well-defined map on homology (A chain map induces a well-defined map on homology).

Proof

technique · direct
1.1L1givenconstruct

The maps Hn(A)→Hn(B) and Hn(B)→Hn(C) are defined by [L1], and the connecting map ∂n is defined by The connecting morphism in homology. Thus the displayed sequence exists in every degree.

2.1L2step 1.1algebra

For each integer n, [L2] gives exactness at Hn(A), Hn(B), Hn(C), and Hn−1(A). Therefore every four-term window around ∂n is exact.

3.1step 2.1algebra∎

Since n was arbitrary, these exact windows concatenate to the displayed bi-infinite exact sequence.

Depends on

Used by

…and 3 more results.

Dependency tree · two levels

13 results within two dependency steps of this one, each drawn at its shortest distance from it. An arrow runs from a result to what uses it, so the chart reads left to right and ends at this result, which carries a heavier outline. Every node is a link to that result. Click elsewhere on the chart to enlarge it.

Sources