 Strong converse for fixed-rate source coding

For a finite-alphabet IID source of entropy $H$, fixed-length block codes of rate $R<H$ have reconstruction success probability tending to zero. At most $2^{nR}$ strings can be correctly reconstructed. Their typical probability is at most $2^{nR}{2}^{-n(H-\delta )}$, and the atypical probability tends to zero; choose $0<\delta <H-R$.

// Target: algebra.bigb