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We prove an analog of the Tits alternative for rational functions. In particular, we show that if $S$ is a finitely generated semigroup of rational functions over the complex numbers, then either $S$ has polynomially bounded growth or $S$…

Number Theory · Mathematics 2021-03-19 Jason P. Bell , Keping Huang , Wayne Peng , Thomas J. Tucker

For a finite alphabet $\mathcal{A}$ and shift $X\subseteq\mathcal{A}^{\mathbb{Z}}$ whose factor complexity function grows at most linearly, we study the algebraic properties of the automorphism group ${\rm Aut}(X)$. For such systems, we…

Dynamical Systems · Mathematics 2014-11-04 Van Cyr , Bryna Kra

Two cellular automata are strongly conjugate if there exists a shift-commuting conjugacy between them. We prove that the following two sets of pairs $(F,G)$ of one-dimensional one-sided cellular automata over a full shift are recursively…

Computational Complexity · Computer Science 2017-10-24 Joonatan Jalonen , Jarkko Kari

For a subshift over a finite alphabet, a measure of the complexity of the system is obtained by counting the number of nonempty cylinder sets of length $n$. When this complexity grows exponentially, the automorphism group has been shown to…

Dynamical Systems · Mathematics 2014-03-04 Van Cyr , Bryna Kra

We consider Turing machines as actions over configurations in $\Sigma^{\mathbb{Z}^d}$ which only change them locally around a marked position that can move and carry a particular state. In this setting we study the monoid of Turing machines…

Group Theory · Mathematics 2019-04-26 Sebastián Barbieri , Jarkko Kari , Ville Salo

Let $\Gamma$ be a finitely generated group acting properly discontinuously by isometries on a visibility CAT(0) space $X$ that satisfies the bounded packing property. We prove that $\Gamma$ satisfies the Tits alternative: it is either…

Group Theory · Mathematics 2025-10-02 Ran Ji , Yunhui Wu

Let $G$ be a group and let $A$ be a finite-dimensional vector space over an arbitrary field $K$. We study finiteness properties of linear subshifts $\Sigma \subset A^G$ and the dynamical behavior of linear cellular automata $\tau \colon…

Dynamical Systems · Mathematics 2024-04-05 Tullio Ceccherini-Silberstein , Michel Coornaert , Xuan Kien Phung

We study implications of expansiveness and pointwise periodicity for certain groups and semigroups of transformations. Among other things we prove that every pointwise periodic finitely generated group of cellular automata is necessarily…

Dynamical Systems · Mathematics 2017-06-30 Tom Meyerovitch , Ville Salo

We study limit sets of stable cellular automata standing from a symbolic dynamics point of view where they are a special case of sofic shifts admitting a steady epimorphism. We prove that there exists a right-closing almost-everywhere…

Dynamical Systems · Mathematics 2019-02-20 Alexis Ballier

We survey some properties of the automorphism groups of compact Kaehler manifolds. In particular, we present recent results by Keum, Oguiso and Zhang on the structure of these groups from the Tits alternative point of view. Several other…

Algebraic Geometry · Mathematics 2012-10-26 Tien-Cuong Dinh

The automorphism group of a one dimensional shift space over a finite alphabet exhibits different types of behavior: for a large class with positive entropy, it contains a rich collection of subgroups, while for many shifts of zero entropy,…

Dynamical Systems · Mathematics 2017-08-11 Van Cyr , John Franks , Bryna Kra

We show that two-dimensional Artin groups satisfy a strengthening of the Tits alternative: their subgroups either contain a non-abelian free group or are virtually free abelian of rank at most $2$. When in addition the associated Coxeter…

Group Theory · Mathematics 2023-08-31 Alexandre Martin

We discuss the set of subgroups of the automorphism group of a full shift, and submonoids of its endomorphism monoid. We prove closure under direct products in the monoid case, and free products in the group case. We also show that the…

Dynamical Systems · Mathematics 2015-07-06 Ville Salo

This article initiates a geometric study of the automorphism groups of general graph products of groups, and investigates the algebraic and geometric structure of automorphism groups of cyclic product of groups. For a cyclic product of at…

Group Theory · Mathematics 2018-03-21 Anthony Genevois , Alexandre Martin

It is known that a group shift on a polycyclic group is necessarily of finite type. We show that, for trivial reasons, if a group does not satisfy the maximal condition on subgroups, then it admits non-SFT abelian group shifts. In…

Group Theory · Mathematics 2018-09-25 Ville Salo

The proof of the Tits alternative for $Out(F_n)$ is completed. The main tool is a Kolchin type theorem, proved in this paper. It states that a finitely generated subgroup of $Out(F_n)$ consisting of unipotent automorphisms can be conjugated…

Geometric Topology · Mathematics 2007-05-23 Mladen Bestvina , Mark Feighn , Michael Handel

We consider the range of possible dynamics of cellular automata (CA) on two-sided beta-shifts $S_\beta$. We show that any reversible CA $F:S_\beta\to S_\beta$ has an almost equicontinuous direction whenever $S_\beta$ is not sofic. This has…

Dynamical Systems · Mathematics 2020-01-28 Johan Kopra

We show that the image of a subshift $X$ under various injective morphisms of symbolic algebraic varieties over monoid universes with algebraic variety alphabets is a subshift of finite type, resp. a sofic subshift, if and only if so is…

Dynamical Systems · Mathematics 2021-12-17 Xuan Kien Phung

We study the automorphisms of graph products of cyclic groups, a class of groups that includes all right-angled Coxeter and right-angled Artin groups. We show that the group of automorphism generated by partial conjugations is itself a…

Group Theory · Mathematics 2009-10-27 Ruth Charney , Kim Ruane , Nathaniel Stambaugh , Anna Vijayan

In this article we study the automorphism group ${\rm Aut}(X,\sigma)$ of subshifts $(X,\sigma)$ of low word complexity. In particular, we prove that Aut$(X,\sigma)$ is virtually $\mathbb{Z}$ for aperiodic minimal subshifts and certain…

Dynamical Systems · Mathematics 2015-07-13 Sebastián Donoso , Fabien Durand , Alejandro Maass , Samuel Petite