Very badly ordered cycles of interval maps

Sourav Bhattacharya; Alexander Blokh

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arXiv · 1908.06145

Very badly ordered cycles of interval maps

Sourav Bhattacharya·Alexander Blokh

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Abstract

We prove that a periodic orbit $P$ with coprime over-rotation pair is an over-twist periodic orbit iff the $P$-linear map has the over-rotation interval with left endpoint equal to the over-rotation number of $P$. We then show that this result fails if the over-rotation pair of $P$ is not coprime. Examples of patterns with non-coprime over-rotation pairs are given so that these patterns have no block structure over over-twists but have over-rotation number equal to the left endpoint of the forced over-rotation interval (such patterns are called \emph{very badly ordered}). This presents a situation in which the results about over-rotation numbers on the interval and those about classical rotation numbers for circle degree one maps are different. In the end we elucidate a rigorous description of the strongest unimodal pattern that corresponds to a given over-rotation interval and use it to construct unimodal very badly ordered patterns with arbitrary non-coprime over-rotation pair.

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Sourav Bhattacharya, Alexander Blokh. 2019-08-16. Very badly ordered cycles of interval maps. https://arxiv.org/abs/1908.06145

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