P( |Bn) = 1. n=1 12. Suppose C is a class of subsets of 2 and suppose B C2 satisfies BE o (C). Show that there exists a countable class CB C C such that B E O(CB). Hint: Define G := {BC N:3 countable...

Extracted text: P( |Bn) = 1. n=1 12. Suppose C is a class of subsets of 2 and suppose B C2 satisfies BE o (C). Show that there exists a countable class CB C C such that B E O(CB). Hint: Define G := {BC N:3 countable CB CC such that Be o(CB)}. Show that G is a o-field that contains C. 13 IE LD