SLIDING BLOCK-CODES BETWEEN CONSTRAINED SYSTEMS

The work of Karabed and Marcus on constructing finite-state codes between constrained systems called sofic systems is continued. It is shown that if SIGMA is a shift of finite type and S is a sofic system with k/n = h(S)/h(SIGMA), where h denotes entropy, there is a noncatastrophic finite-state invertible code from SIGMA to S at rate k : n if. 1) SIGMA and S satisfy a certain algebraic condition involving dimension groups, and 2) SIGMA and S satisfy a certain condition on their periodic points. Moreover, if S is an almost finite type sofic system then the decoder can be sliding block.