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We provide a new, dynamical criterion for the radial rapid decay property. We work out in detail the special case of the group $\Gamma := \mathbf{SL}_2(A)$, where $A := \mathbb{F}_q[X,X^{-1}]$ is the ring of Laurent polynomials with…

Group Theory · Mathematics 2022-06-28 Adrien Boyer , Antoine Pinochet Lobos , Christophe Pittet

The unitary representation theory of locally compact contraction groups and their semi-direct products with $\mathbb{Z}$ is studied. We put forward the problem of completely characterising such groups which are type I or CCR and this…

Group Theory · Mathematics 2025-03-28 Max Carter

We construct families of rational functions $f \colon \bP^1_k \to \bP^1_k$ of degree $d \geq 2$ over a perfect field $k$ whose associated fixed-point processes fail to be martingales. Conversely, for any normal variety $X \subset…

Number Theory · Mathematics 2026-04-09 Jianfei He , Zheng Zhu

We show the existence of and explicitly construct generic polynomials for various groups, over fields of positive characteristic. The methods we develop apply to a broad class of connected linear algebraic groups defined over finite fields…

Number Theory · Mathematics 2016-01-19 Eric Y. Chen , J. T. Ferrara , Liam Mazurowski

We investigate graded retracts of polytopal algebras (essentially the homogeneous rings of affine cones over projective toric varieties) as polytopal analogues of vector spaces. In many cases we show that these retracts are again polytopal…

Commutative Algebra · Mathematics 2007-05-23 Winfried Bruns , Joseph Gubeladze

We consider the class of countable groups possessing an action on a finite product of hyperbolic graphs where every infinite order element acts loxodromically. When the graphs are locally finite, we obtain strong structure theorems for the…

Group Theory · Mathematics 2020-09-23 J. O. Button

We prove that the iterated monodromy group of the polynomial $z^2+i$ is just-infinite, regular branch and does not have the congruence subgroup property. This yields the first example of an iterated monodromy group of a polynomial with…

Group Theory · Mathematics 2025-05-27 Santiago Radi

We study profinite actions of residually finite groups in terms of weak containment. We show that two strongly ergodic profinite actions of a group are weakly equivalent if and only if they are isomorphic. This allows us to construct…

Group Theory · Mathematics 2011-09-20 Miklós Abért , Gábor Elek

We study algebraic isomonodromic deformations of flat logarithmic connections on the Riemann sphere with $n\geq 4$ poles, for arbitrary rank. We introduce a natural property of algebraizability for the germ of universal deformation of such…

Algebraic Geometry · Mathematics 2016-03-01 Gaël Cousin

We give a complete description of the arboreal Galois representation of a certain postcritically finite cubic polynomial over a large class of number fields and for a large class of basepoints. This is the first such example that is not…

Number Theory · Mathematics 2017-12-22 Robert L. Benedetto , Xander Faber , Benjamin Hutz , Jamie Juul , Yu Yasufuku

This paper introduces iterated monodromy groups for transcendental functions and discusses them in the simplest setting, for post-singularly finite exponential functions. These groups are self-similar groups in a natural way, based on an…

Dynamical Systems · Mathematics 2020-04-28 Bernhard Reinke

We characterize group compactifications of discrete groups for which there exists an equivariant retraction onto the boundary. In particular, we prove an equivariant analogue of Brouwer's No-Retraction theorem for large classes of group…

Group Theory · Mathematics 2025-09-15 Yair Hartman , Aranka Hrušková , Mehrdad Kalantar , Tomer Zimhoni

In this paper we deal with branched coverings over the complement to finitely many exceptional points on the Riemann sphere having the property that the local monodromy around each of the branching points is of finite order. To such a…

Algebraic Geometry · Mathematics 2012-07-06 Yuri Burda , Askold Khovanskii

Jones conjectures the arboreal representation of a degree two rational map will have finite index in the full automorphism group of a binary rooted tree except under certain conditions. We prove a version of Jones' Conjecture for quadratic…

Number Theory · Mathematics 2018-04-20 Jamie Juul , Holly Krieger , Nicole Looper , Michelle Manes , Bianca Thompson , Laura Walton

We establish three independent results on groups acting on trees. The first implies that a compactly generated locally compact group which acts continuously on a locally finite tree with nilpotent local action and no global fixed point is…

Group Theory · Mathematics 2018-12-19 Pierre-Emmanuel Caprace , Phillip Wesolek

We consider groups that act on spherically symmetric rooted trees and study the associated representation of the group on the space of locally constant functions on the boundary of the tree. We introduce and discuss the new notion of…

Group Theory · Mathematics 2020-03-25 Steffen Kionke

In this article we compare the known dynamical polynomial time algorithm for the game-over attack strategy, to that of the brute force approach; of checking all the ordered rooted subtrees of a given tree that represents a given computer…

Combinatorics · Mathematics 2023-12-19 Geir Agnarsson , Elie Alhajjar , Aleyah Dawkins

We consider the computation of roots of polynomials expressed in the Chebyshev basis. We extend the QR iteration presented in [Eidelman, Y., Gemignani, L., and Gohberg, I., Numer. Algorithms, 47.3 (2008): pp. 253-273] introducing an…

Numerical Analysis · Mathematics 2021-04-30 Angelo Casulli , Leonardo Robol

We investigate the finite-dimensional representation theory of two-parameter quantum orthogonal and symplectic groups that we found in [BGH] under the assumption that $rs^{-1}$ is not a root of unity and extend some results [BW1, BW2]…

Quantum Algebra · Mathematics 2010-03-31 Nantel Bergeron , Yun Gao , Naihong Hu

We say that a finitely generated group $G$ has property (QT) if it acts isometrically on a finite product of quasi-trees so that orbit maps are quasi-isometric embeddings. A quasi-tree is a connected graph with path metric quasi-isometric…

Group Theory · Mathematics 2020-10-15 Mladen Bestvina , Kenneth Bromberg , Koji Fujiwara