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.
FALSE: the homology functor is exact on short exact sequences of complexes
Statement
The homology functor is exact on short exact sequences of complexes.
Facts & Assumptions
Given: The canonical cone sequence of the identity map on .
The statement refuted is: the homology functor is exact on short exact sequences of complexes.
Short exact sequences of complexes give long exact homology sequences with a connecting morphism (The long exact sequence in homology).
For the cone sequence of the identity map, the connecting morphism is the shifted identity up to sign, hence nonzero (The cone connecting map agrees with the shifted identity up to the declared sign).
Refutation
If homology were exact in the short sense claimed in [A1], then the connecting morphism in every long exact sequence from [L1] would be zero.
But [L2] gives a short exact sequence of complexes whose connecting morphism is nonzero. So the homology functor is not exact on short exact sequences of complexes; instead it participates in the long exact sequence of [L1]. Therefore [A1] is false.
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)