=+

(c) Suppose that A is a Borel set contained in H. If A( A) > 0, then D(A)

contains an interval (0, €); but then some 024 + 1 lies in (0,€) CD(A) CD(H), and so 02k+ 1 =h1 - h2 =h| eh2 = (s, @ 82 ) ℮ (s2 @ "2",) for some h1, h2 in H and some $1, s2 in S. Deduce that $1 =52 and obtain a contradiction.

Conclude that À , (H) = 0.