Abstract
Using the follower/predecessor/extender set sequences defined by the first author, we define quantities which we call the follower/predecessor/extender entropies, which can be associated to any shift space. We analyze the behavior of these quantities under conjugacies and factor maps, most notably showing that extender entropy is a conjugacy invariant and that having follower entropy zero is a conjugacy invariant. We give some applications, including examples of shift spaces with equal entropy which can be distinguished by extender entropy, and examples of shift spaces which can be shown to not be isomorphic to their inverse by using follower/predecessor entropy.
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References
Buzzi, J.: Subshifts of quasi-finite type. Invent. Math. 159(2), 369–406 (2005)
Fogg, N.P.: Substitutions in Dynamics, Arithmetics and Combinatorics, volume 1794 of Lecture Notes in Mathematics. Springer, Berlin (Edited by Berthé, V., Ferenczi, S., Mauduit, C., Siegel, A.) (2002)
French, T.: Characterizing follower and extender set sequences. Dyn. Syst. 31(3), 293–310 (2016)
French, T.: Follower, predecessor, and extender set sequences of \(\beta \)-Shifts. arXiv:1701.01173 (2017)
Kass, S., Madden, K.: A sufficient condition for non-soficness of higher-dimensional subshifts. Proc. Am. Math. Soc. 141(11), 3803–3816 (2013)
Parry, W.: On the \(\beta \)-expansions of real numbers. Acta Math. Acad. Sci. Hungar. 11, 401–416 (1960)
Rényi, A.: Representations for real numbers and their ergodic properties. Acta Math. Acad. Sci. Hungar 8, 477–493 (1957)
Schmeling, J.: Symbolic dynamics for \(\beta \)-shifts and self-normal numbers. Ergodic Theory Dyn. Syst. 17(3), 675–694 (1997)
Spandl, C.: Computing the topological entropy of shifts. MLQ Math. Log. Q. 53(4–5), 493–510 (2007)
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Communicated by H. Bruin.
The second author gratefully acknowledges the support of NSF Grant DMS-1500685.
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French, T., Pavlov, R. Follower, predecessor, and extender entropies. Monatsh Math 188, 495–510 (2019). https://doi.org/10.1007/s00605-018-1224-5
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DOI: https://doi.org/10.1007/s00605-018-1224-5