Name of the formula which links an event with an alternatives' system Given an event $B$ and a system of alternatives (I hope this is the right name in english, otherwise tell me the right one please) $(A_i)_{i=1}^n$, the following formula is valid:
$$
P(B \, | \, \Omega) = P(B \, | \, \Omega \, \cap \, A_1) \, P(A_1 \, | \, \Omega) +
... +
P(B \, | \, \Omega \, \cap \, A_n) \, P(A_n \, | \, \Omega)
$$
I'd like to know the english name of the above formula.

The "system of alternatives" is a partition and the probability equation is the law of total probability.  (In the present case, it is expressed with all events explicitly conditioning on $\Omega$.)
