Rocky Mountain Journal of Mathematics

A short proof of a theorem of Cobham on substitutions

Ethan M. Coven, Andrew Dykstra, and Michelle Lemasurier

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This paper is concerned with the lengths of constant length substitutions that generate topologically conjugate systems. We show that if the systems are infinite, then these lengths must be powers of the same integer. This result is a dynamical formulation of a special case of a 1969 theoretical computer science result of Cobham [{\bf1}]. Our proof is rather simple.

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Rocky Mountain J. Math., Volume 44, Number 1 (2014), 19-22.

First available in Project Euclid: 2 June 2014

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Coven, Ethan M.; Dykstra, Andrew; Lemasurier, Michelle. A short proof of a theorem of Cobham on substitutions. Rocky Mountain J. Math. 44 (2014), no. 1, 19--22. doi:10.1216/RMJ-2014-44-1-19.

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