We consider the problem of computing with faulty components in the con
text of the Boolean decision tree model, in which cost is measured by
the number of input bits queried, and the responses to queries are fau
lty with a fixed probability. We show that if f can be represented in
k-DNF form and in j-CNF form, then O(n log(min(k, j)/q)) queries suffi
ce to compute f with error probability less than q, where n is the num
ber of input bits. (C) 1994 John Wiley & Sons, Inc.