=+

(c) Suppose that ((t)|=(((')| =1 for incommensurable t and t' (t=0,

[' +0, t/t' irrational). Show that P[X = c] = 1 for some constant c.

26.2. If p( -, x] =p[ -x, ) for all x (which implies that u( A) = p(-A) for all A € 22 ), then u is symmetric. Show that this holds if and only if the characteristic function is real.