he considered three discs r, s, and t as typical subsets of a set u. the intersections of these discs and their complements divide u into 8 non-overlapping regions, the unions of which give 256 different boolean combinations of the original sets r, s, t.

Please write the text above using proper case.
He considered three discs R, S, and T as typical subsets of a set U. The intersections of these discs and their complements divide U into 8 non-overlapping regions, the unions of which give 256 different Boolean combinations of the original sets R, S, T.