The source coding game with a cheating switcher

Berger´s paper ´The Source Coding Game´, IEEE Trans. Inform. Theory, 1971, considers the problem of finding the rate-distortion function for an adversarial source comprised of multiple known IID sources. The adversary, called the ´switcher´, was allowed only causal access to the source realizations and the rate-distortion function was obtained through the use of a type covering lemma. In this paper, the rate-distortion function of the adversarial source is described, under the assumption that the switcher has non-causal access to all source realizations. The proof utilizes the type covering lemma and simple conditional, random ´switching´ rules. The rate-distortion function is once again the maximization of the R(D) function for a region of attainable IID distributions.