On a lower bound for the redundancy of reliable networks with noisy gates

We provide a proof that a logarithmic redundancy factor is necessary for the reliable computation of the parity function by means of a network with noisy gates. This is the same as the main result in [1], except that the analysis therein seems to be not entirely correct. t Department of Computer Science, University of British Columbia, Vancouver, British Columbia V6T 1W5, Canada. Research supported by the NSERC under Grant OGP-0041640. Z Laboratory for Information and Decision Systems, Massachusetts Institute of Technology, Cambridge, Mass. 02139, USA. Research supported by the NSF under Grant ECS-8552419, with matching funds from Bellcore Inc. and Du Pont, and by the ARO under Grant DAAL03-86-K0171.