Is this correct:
Let $ S = [1, 2, 3], X = I_{{1}}, Y = I_{{2,3}}, Z = I_{{1,2}}. $ Let $ W = X - Y + Z. $ ($ I_A $ is the indicator function of A.) Compute $W(1), W(2)$ and $W(3).$
$W(1) = 1 - 0 + 1 = 2$, $W(2) = 0 - 1 + 1 = 0$, $W(3) = 0 - 1 + 0 = -1$
?
My text book doesn't agree with me and gives the solutions $ W(1) = 1$ and $W(3) = 0.$