DefinitionDefinition: Literature-sourcedProof: Not applicableaudited 2026-08-13
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.
Invariant basis number and the rank of a free module
Definition
A unital ring has invariant basis number for finite bases if for all , as left -modules (The free module on a set and its standard basis, Module homomorphism and isomorphism, kernel, image and cokernel).
When has this property and a free module has a finite basis of elements, its rank is . This definition makes no assertion about equality of arbitrary infinite bases.