ThmDex – An index of mathematical definitions, results, and conjectures.
Formulation F3655 on D24: Ring
F3655
Formulation 0
An D21: Algebraic structure $R = (X, f, g)$ is a ring if and only if
(1) $\forall \, x, y \in X : f(x, y) \in X$ (D20: Enclosed binary operation)
(2) $\forall \, x, y \in X : g(x, y) \in X$ (D20: Enclosed binary operation)
(3) $\forall \, x, y, z \in X : g(x, f(y, z)) = f(g(x, y), g(x, z))$ (D555: Left-distributive binary operation)
(4) (R3) $\forall \, x, y, z \in X : g(x, f(y, z)) = f(g(x, y), g(x, z))$ (D555: Left-distributive binary operation)
(5) $\forall \, x, y, z \in X : f(f(x, y), z) = f(x, f(y, z))$ (D488: Associative binary operation)
(6) $\forall \, x, y, z \in X : g(g(x, y), z) = g(x, g(y, z))$ (D488: Associative binary operation)
(7) $\forall \, x, y \in X : f(x, y) = f(y, x)$ (D489: Commutative binary operation)
(8) $\exists \, 0_R \in X : \forall \, x \in X : f(0_R, x) = f(x, 0_R) = x$ (D39: Identity element)
(9) $\forall \, x \in X : \exists \, {-x} \in X: f(-x, x) = f(x, -x) = 0_R$ (D40: Inverse element)