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.
Commutative ring
Definition
A ring (Ring: an abelian group under addition and a monoid under multiplication, with multiplication distributing over addition on both sides) is commutative when its multiplication is commutative (Binary operation on a set; associativity, commutativity, and a subset closed under the operation):
Addition is commutative in every ring, by axiom (R1), so the word refers to multiplication alone.
Remarks
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One of the two distributive laws becomes redundant. In a commutative ring the right law follows from the left one, since . Both are still stated in Ring: an abelian group under addition and a monoid under multiplication, with multiplication distributing over addition on both sides, because a ring is not assumed commutative there.
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Every field is a commutative ring (Every field is a commutative ring with ; it is an integral domain, and it is a commutative division ring), and , and are commutative rings; the companion page records each of those as an instance. The quaternions are a ring that is not commutative (The quaternions : real quadruples with componentwise addition and an explicit multiplication formula matching the table on , is a division ring that is not commutative, hence not a field: for , while and ).
Depends on
Used by
- Global sections of projective twists Corollary
- Intermediate cohomology of projective twists vanishes Corollary
- Top cohomology of projective twists Corollary
- A local ring is a nonzero commutative ring with a unique maximal ideal Definition
- Algebras over a commutative ring, central structure maps, and algebra homomorphisms Definition
- An R-linear action of G on a left R-module, and a G-module over R Definition
- Balanced maps from a right module and a left module, and bilinear maps over a commutative ring Definition
- Bounded polynomial-factorization categories and the cotangent module diagram Definition
- Colourings, weight functions, and the pattern inventory Definition
- Column-multilinear, alternating, normalized and antisymmetric functions on square matrices over a commutative ring Definition
- Commutative Hopf algebras over a field Definition
- Derivation of an algebra Definition
- Elementary ideals of a finitely presented module Definition
- Entrywise ring-matrix operations, rectangular matrix products, identity matrices and transpose Definition
- Finite rectangular matrices over a commutative ring, their entries, rows and columns Definition
- Finite weighted directed multigraphs, weighted walks and their transfer matrices Definition
- Formal power series over a commutative ring and the coefficient-extraction functional [xⁿ] Definition
- Multiplicative subsets and the localisation S⁻¹R as equivalence classes of fractions Definition
- Noetherian commutative rings and modules Definition
- Ordered ring: a ring with a total order compatible with addition and with positives closed under multiplication Definition
- Prime ideals and maximal ideals in a commutative ring Definition
- R-orientation of a topological manifold Definition
- Row swaps, arbitrary row scalings and row additions over a commutative ring, with reversible elementary cases distinguished Definition
- Simplicial objects, simplicial commutative rings and homotopy groups Definition
- Singular knots and Vassiliev derivatives Definition
- Square-zero extensions, small extensions and first-order thickenings Definition
- Subfield: a subring of a field closed under inverses of its nonzero elements, and therefore a field with the restricted operations Definition
- Symmetric polynomials as the invariants of variable permutations Definition
- The category FI and FI-modules over a commutative ring Definition
- The center of a ring Definition
- The cotangent complex of a ring map Definition
- The degenerate affine Hecke algebra Definition
- The group ring R[G] of finitely supported formal R-linear combinations of group elements Definition
- The incidence functions I(P,R) of a locally finite poset and their convolution Definition
- The Laurent polynomial ring as the principal localisation of Z[t] at t Definition
- The polynomial ring over a commutative ring as finitely supported coefficient sequences with convolution Definition
- The polynomial ring R[xᵢ:i∈ I] as finitely supported coefficient families on monomials Definition
- The product ring R × S with componentwise operations, its identity (1_R, 1_S) and its units R^× × S^× Definition
- The R-module Hom_R(M,N) over a commutative ring Definition
- The radical of an ideal Definition
…and 41 more results.
Dependency tree · two levels
10 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
- Commutative ring (Wikipedia) (standard reference, not scraped)
- Thomas W. Judson, Abstract Algebra: Theory and Applications, §16.3: Rings (standard reference, not scraped)