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Entropy bounds for endomorphisms commuting with K actions
by
Gary Morris
University of East Anglia
Coauthors: Tomm Ward
Shereshevsky has conjectured that a two dimensional cellular automata must have zero or infinite entropy. We prove a general result of this sort for endomorphisms commuting with a Z^2 action of completely positive entropy, which proves the conjecture of Shereshevsky for additive cellular automata. When the underlying group is connected, the result is related to Lehmer's problem. The method used in the cellular automata case also gives a proof of Shereshevsky's conjecture for a certain class of (non-additive) cellular automata.
Date received: February 25, 1998
Copyright © 1998 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cabf-12.