Axiom:Sigma-Ring Axioms/Formulation 2

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

$\Sigma$ satisfies the $\sigma$-ring axioms  $\Sigma$ satisifes the following 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