Unformatted text preview: 0 and &lt; 1p there is a binary code C of rate at least and a decoding algorithm A ( C ) such that max x C P x A ( C ) ( C ) &lt; . Hint: Choose an appropriate with &lt; &lt; 1p . Then ( * ) guarantees codes D of rate at least with avg x D P x A ( D ) ( D ) &lt; / 2. A candidate for C would then be the code consisting of those  D  / 2 codewords from D with small values of P x A ( D ) ( D ). (That is, C D is chosen so that for all x C and all z D \ C we have P x A ( D ) ( D ) P z A ( D ) ( D ).)...
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 Spring '11
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 Cryptography, Binary numeral system, Px, Encodings

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