=+2.17. Suppose that P is a probability measure on a field ", that A1, A2 ,..., and A = U ,, A, lie in F, and that the A ,, are nearly disjoint in the sense that P(A„OA„) =0 for m + n. Show that P(A) =C ,, P(A ,, ).

2.18. Stochastic arithmetic. Define a set function P ,, on the class of all subsets of 2 = {1,2 ,... } by

(2.34)