Ergodic Theory and Dynamical Systems

Research Article

Resolving factor maps for shifts of finite type with equal entropy

Jonathan Ashleya1

a1 University of Washington, Seattle, Washington 98195, USA

Abstract

We sharpen a result of Boyle, Marcus and Trow as follows. An aperiodic shift of finite type ΣA factors onto another ΣB with equal entropy by a 1-to-l almost everywhere right-closing map if and only if (1) the dimension group for ΣB is a quotient of that for ΣA; and (2) ΣA and ΣB satisfy the trivial periodic point condition for existence of a shift-commuting map from ΣA to ΣB.

(Received May 16 1989)

Footnotes

† Supported by an NSF Post-doctoral Fellowship in the Mathematical Sciences.