Rate Region of the Vector Gaussian One-Helper Source-Coding Problem
  We determine the rate region of the vector Gaussian one-helper source-coding problem under a covariance matrix distortion constraint. The rate region is achieved by a simple scheme that separates the lossy vector quantization from the lossless spatial compression. The converse is established by extending and combining three analysis techniques that have been employed in the past to obtain partial results for the problem. 
Md. Saifur Rahman and Aaron B. Wagner
cs.IT math.IT