Counting conjugacy classes of fully irreducibles: double exponential growth

Fuente: arXiv
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Main Authors: Kapovich, Ilya, Pfaff, Catherine
Format: Preprint
Published: 2018
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author Kapovich, Ilya
Pfaff, Catherine
author_facet Kapovich, Ilya
Pfaff, Catherine
contents Inspired by results of Eskin and Mirzakhani counting closed geodesics of length $\le L$ in the moduli space of a fixed closed surface, we consider a similar question in the $Out(F_r)$ setting. The Eskin-Mirzakhani result can be equivalently stated in terms of counting the number of conjugacy classes (within the mapping class group) of pseudo-Anosovs whose dilitations have natural logarithm $\le L$. Let $\mathfrak N_r(L)$ denote the number of $Out(F_r)$-conjugacy classes of fully irreducibles satisfying that the natural logarithm of their dilatation is $\le L$. We prove for $r\ge 3$ that as $L\to\infty$, the number $\mathfrak N_r(L)$ has double exponential (in $L$) lower and upper bounds. These bounds reveal behavior not present in the surface setting or in classical hyperbolic dynamical systems.
format Preprint
id arxiv_https___arxiv_org_abs_1801_07471
institution arXiv
publishDate 2018
record_format arxiv
spellingShingle Counting conjugacy classes of fully irreducibles: double exponential growth
Kapovich, Ilya
Pfaff, Catherine
Group Theory
Dynamical Systems
Geometric Topology
20F65 (Primary), 57M, 37B, 37D (Secondary)
Inspired by results of Eskin and Mirzakhani counting closed geodesics of length $\le L$ in the moduli space of a fixed closed surface, we consider a similar question in the $Out(F_r)$ setting. The Eskin-Mirzakhani result can be equivalently stated in terms of counting the number of conjugacy classes (within the mapping class group) of pseudo-Anosovs whose dilitations have natural logarithm $\le L$. Let $\mathfrak N_r(L)$ denote the number of $Out(F_r)$-conjugacy classes of fully irreducibles satisfying that the natural logarithm of their dilatation is $\le L$. We prove for $r\ge 3$ that as $L\to\infty$, the number $\mathfrak N_r(L)$ has double exponential (in $L$) lower and upper bounds. These bounds reveal behavior not present in the surface setting or in classical hyperbolic dynamical systems.
title Counting conjugacy classes of fully irreducibles: double exponential growth
topic Group Theory
Dynamical Systems
Geometric Topology
20F65 (Primary), 57M, 37B, 37D (Secondary)
url https://arxiv.org/abs/1801.07471