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).
Depends on
Used by
- For A∈ Mₙ(R), the coordinate endomorphism T_A:Rⁿ→ Rⁿ, with det(T_A):=det(A) and adj(T_A):=T_adj(A) Definition
- The adjugate of an operator on a positive-dimensional finite-dimensional vector space, defined by the adjugate matrix in any basis Definition
- The adjugate gives the inverse of a 3×3 rational matrix with determinant 3 Example
- For A∈ Mₙ(R) and columns u,v over a commutative ring, det(A+uv^T)=det(A)+v^Tadj(A)u Lemma
- Laplace expansion computes the determinant along every row and every column over a commutative ring Theorem
Dependency tree · next 3 levels
Direct dependencies and their dependencies through the next three levels: 57 results over 13 levels. An arrow runs from a result to what uses it, and this result sits at the bottom with a heavier outline. Click the chart to enlarge it.
Sources
- Interactive Linear Algebra (standard reference, not scraped)
- András Pál, Introduction to Commutative Algebra (standard reference, not scraped)