Basic Axioms of Probability:
(a) for any set A.
(b) , where is the sample space.
(c) If is a sequence of mutually exclusive events, that is for all i and j different: we have the finite additivity property:
If E and F are disjoint, (mutally exclusive),
We define a partition of the sample space to be a sequence of pairwise disjoint sets whose union is . Property 5:
If forms a partition of then: