Abstract
A lower boundR_L (D)is obtained to the rate-distortion functionR(D)of a finite-alphabet stationary source with respect to a context-dependent fidelity criterion. For equiprobable memoryless sources and modular distortion measures,R(D) = R_L (D)for allD. It is conjectured that, for a broad class of finite-alphabet sources and context-dependent fidelity criteria, there exists a critical distortionD_c > 0such thatR(D) = R_L (D)forD \leq D_{c^\cdot}. The case of a binary source and span-2 distortion measure is treated in detail. Among other results a coding theorem is proved that establishes thatR(0) = \log (2/r_g), wherer_gis the golden ratio,(1 + \sqrt{5})/2.

This publication has 3 references indexed in Scilit: