Axiom:Sigma-Ring Axioms/Formulation 2

Definition
Let $\Sigma$ be a system of sets.

$\Sigma$ is a $\sigma$-ring the following axioms are satisfied:

These criteria are called the $\sigma$-ring axioms.

Also see

 * Axiom:Sigma-Ring Axioms/Formulation 1, for an alternative formulation of the axioms


 * Definition:Sigma-Ring


 * Equivalence of Definitions of Sigma-Ring