p30 of InfoTh notes. Pe = sum_{k != j} P(Y = y_k | X = x_j) = sum_{k != j}p(y_k | x_j) p(x_j). Clearly there's some difference between P(Y = y_k | X = x_j) and p(y_k | x_j), but what is it? Thanks, Peter ===== Peter Taylor pjt33@cam.ac.uk