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.
Deleted-row-and-column minors, cofactors, the cofactor matrix and the adjugate over a commutative ring
Definition
Let be a commutative ring, let , and let , with rows and columns indexed by (Finite rectangular matrices over a commutative ring, their entries, rows and columns).
For , the deleted-row-and-column matrix is obtained by deleting row and column . The minor and cofactor at are
where the sign is taken in by parity: when is even and when is odd. Writing this as is the usual abbreviation; it is the ring element raised to a natural-number power in , not a real power. When , is the unique matrix and its determinant is defined locally to be . For , the determinant is the published matrix determinant (For , the determinant over a commutative ring by the Leibniz formula, and for a real matrix).
The cofactor matrix is , and the adjugate is
using the published transpose operation (Entrywise ring-matrix operations, rectangular matrix products, identity matrices and transpose).