Output noise in addition to intended output. The 'noise' is the information discarded by the logical operation and must provide enough detail to recreate the i

Output noise in addition to intended output. The 'noise' is the information discarded by the logical operation and must provide enough detail to recreate the input conditions from the output. So if an AND gate and the result is 0, you need the noise to contain enough information to indicate whether one of the inputs was 1 or not.