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arXiv 1402.2008math.DS
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一维熵

Entropy in Dimension One

William Thurston

摘要:

本文对单位区间上的后临界有限自映射的拓扑熵进行了分类。具体地说,正实数h是单位区间的后临界有限自映射的拓扑熵当且仅当exp(h)是一个代数整数,至少与exp(h)的任何共轭的绝对值一样大;也就是说,如果exp(h)是一个弱Perron数。后临界有限映射可以选择为所有临界点都在区间(0,1)内的多项式。本文还证明了弱Perron数恰好是exp(h)所表示的数,其中h是自由群的外自同构的遍历训练轨道表示的拓扑熵.

英文摘要:

This paper completely classifies which numbers arise as the topological entropy associated to postcritically finite self-maps of the unit interval. Specifically, a positive real number h is the topological entropy of a postcritically finite self-map of the unit interval if and only if exp(h) is an algebraic integer that is at least as large as the absolute value of any of the conjugates of exp(h); that is, if exp(h) is a weak Perron number. The postcritically finite map may be chosen to be a polynomial all of whose critical points are in the interval (0,1). This paper also proves that the weak Perron numbers are precisely the numbers that arise as exp(h), where h is the topological entropy associated to ergodic train track representatives of outer automorphisms of a free group.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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