TheoremStatement: Literature-sourcedProof: AI-generatedPipeline-generatedprecheck passjudge pass (gpt-5.6-terra)audited 2026-09-01‡ rests on unproved material (inherited)

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.

‡ Rests on 3 statements not proved in this library, by way of the results it cites. This item cites no such statement directly; it depends on results that do. The unproved premises it inherits are ‡ Cohen's first model: an infinite Dedekind-finite set of reals, ‡ Sierpiński 1947: the generalised continuum hypothesis implies the Axiom of Choice and ‡ The continuum hypothesis and its generalisation are independent of ZFC. Each is recorded with a citation to the literature and is not established here, because the track that would prove it has not yet been developed in this library. Everything else in this proof is proved here.

Naturality of the cohomology connecting morphism

Statement

A morphism of short exact sequences of cochain complexes induces a commutative square $\begin{array}{ccc} H^{n} (C) & \overset{\partial^{n}}{\to} & H^{n + 1} (A) \\ ↓ & ↓ \\ H^{n} (C^{'}) & \overset{\partial^{' n}}{\to} & H^{n + 1} (A^{'}) \end{array}$ for every $n \in Z$ .

Facts & Assumptions

Given: A morphism of short exact sequences of cochain complexes.

[L1]

A cochain complex is read as a chain complex by the grading-reversal convention $(C^{♯})_{n} = C^{- n}$ (Cochain complex in an abelian category).

[L2]

The homology connecting morphism is natural under morphisms of short exact sequences (Naturality of the homology connecting morphism).

[L3]

The cohomology connecting maps are the reindexed homology connecting maps (The long exact sequence in cohomology).

Proof

technique · direct

1.1

Apply [L1] to both rows of the given morphism. This turns the cochain ladder into a morphism of short exact sequences of chain complexes.

L1givenconstruct

2.1

The resulting lower-index connecting square commutes by [L2]. Translating back with [L3] gives the upper-index square in the statement.

L2L3step 1.1algebra∎

Depends on

Used by

Nothing in the library uses this result yet.

Dependency tree · two levels

11 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

Charles A. Weibel, Chapter 1 of An Introduction to Homological Algebra (standard reference, not scraped)
The Stacks Project, Section 12.13: Complexes (standard reference, not scraped)
Romyar Sharifi, Homological Algebra (standard reference, not scraped)