Gw mau tau Third axiom dari Probability axioms. Jelasin dalam bahasa sunda

Any countable sequence of mutually disjoint events  satisfies .

That is, the probability of an event set which is the union of other disjoint subsets is the sum of the probabilities of those subsets.  This is called σ-additivity.  If there is any overlap among the subsets this relation does not hold.

For an algebraic alternative to Kolmogorov's approach, see algebra of random variables.