Sequential Recurrence-Based Multidimensional Universal Source Coding of   Lempel-Ziv Type
  We define an algorithm that parses multidimensional arrays sequentially into mainly unrepeated but nested multidimensional sub-arrays of increasing size, and show that the resulting sub-block pointer encoder compresses almost every realization of any finite-alphabet ergodic process on $\mathbb{Z}_{\geq0}^d$ to the entropy, in the limit. 
Tyll Krueger, Guido Montufar, Ruedi Seiler, Rainer Siegmund-Schultze
cs.IT math.IT