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A polynomial automorphism of $\mathbb{A}^n$ over a field of characteristic zero is called co-tame if, together with the affine subgroup, it generates the entire tame subgroup. We prove some new classes of automorphisms, including…

Algebraic Geometry · Mathematics 2017-05-04 Eric Edo , Drew Lewis

Let $M$ be a left $R$-module. We define the \emph{homomorphism submodule graph} $\Gamma_{\mathrm{Hom}}(M)$ as the simple graph whose vertices are the proper submodules of $M$, with an edge between distinct vertices $N_1$ and $N_2$ if and…

Combinatorics · Mathematics 2025-11-12 Shahram Mehry , Mansour Molaeinejad

We construct a modular compactification via stable slc pairs for the moduli spaces of K3 surfaces with a nonsymplectic group of automorphisms under the assumption that some combination of the fixed loci of automorphisms defines an effective…

Algebraic Geometry · Mathematics 2026-02-24 Valery Alexeev , Philip Engel , Changho Han

Let $\mathcal{G}$ denote the variety generated by infinite dimensional Grassmann algebras; i.e., the collection of all unitary associative algebras satisfying the identity $[[z_1,z_2],z_3]=0$, where $[z_i,z_j]=z_iz_j-z_jz_i$. Consider the…

Rings and Algebras · Mathematics 2021-08-13 Nazan Akdogan , Sehmus Findik

In this last article of the series on outer actions of a countable dicrete amenable group on AFD factors, we analyze outer actions of a countable discrete free abelian group on an AFD factor of type $\text{III}_\lambda$, $0<\lambda< 1$, and…

Operator Algebras · Mathematics 2009-03-24 Yoshikazu Katayama , Masamichi Takesaki

The quantum $H_3$ integrable system is a 3D system with rational potential related to the non-crystallographic root system $H_3$. It is shown that the gauge-rotated $H_3$ Hamiltonian as well as one of the integrals, when written in terms of…

Mathematical Physics · Physics 2017-01-05 Marcos A. G. García , Alexander V. Turbiner

We provide an effective algorithm for determining whether an element of the outer automorphism group of a free group is fully irreducible. Our method produces a finite list which can be checked for periodic proper free factors.

Group Theory · Mathematics 2014-07-24 Matt Clay , Johanna Mangahas , Alexandra Pettet

In this paper we prove that a fully irreducible outer automorphism relative to a non-exceptional free factor system acts loxodromically on the relative free factor complex as defined by Handel and Mosher. We also prove a north-south dynamic…

Group Theory · Mathematics 2017-12-29 Radhika Gupta

To any free group automorphism, we associate a universal (cone of) limit tree(s) with three defining properties: first, the tree has a minimal isometric action of the free group with trivial arc stabilizers; second, there is a unique…

Group Theory · Mathematics 2024-12-23 Jean Pierre Mutanguha

We prove that the outer automorphism group of a one-ended hyperbolic group is virtually a hierarchically hyperbolic group (HHG), under mild orientability conditions on the associated JSJ decomposition. This is done by proving that a…

Group Theory · Mathematics 2026-05-25 Ervin Hadziosmanovic , Giorgio Mangioni

We find the shortest realized stretch factor for a fully irreducible $\varphi\in\mathrm{Out}(F_3)$ and show that it is realized by a "principal" fully irreducible element. We also show that it is the only principal fully irreducible…

Group Theory · Mathematics 2025-02-17 Naomi Andrew , Paige Hillen , Robert Alonzo Lyman , Catherine Eva Pfaff

We study finite subgroups of outer automorphisms of free products. We give upper bounds for the orders of these finite subgroups as well as bounds for the orders of individual torsion outer automorphisms under some (necessary) conditions…

Group Theory · Mathematics 2025-06-23 Ioannis Papavasileiou , Dionysios Syrigos

This is the third in a series of papers highlighting the applications of reduced and coreduced modules. Let $R$ be a commutative unital ring and $I$ be an ideal of $R$. We show in different settings that $I$-reduced (resp. $I$-coreduced)…

Commutative Algebra · Mathematics 2025-03-19 David Ssevviiri

A description is given of those sequences ${\Bbb S}= (S(0),S(1),\dots,S(l))$ of simple modules over a finite dimensional algebra for which there are only finitely many uniserial modules with consecutive composition factors…

Representation Theory · Mathematics 2014-07-10 Birge Huisgen-Zimmermann

We prove that the conjugacy problem in Out(Fm) is solvable for the class of outer automorphisms whose restrictions to their polynomial subgroups are of finite order. To do this, we first investigate the structure of suspensions of free…

Group Theory · Mathematics 2026-04-28 Gabriel Bartlett

It was proved that for any finite set of elements of a free product of residually finite groups such that no two of them belong to conjugate cyclic subgroups and each of them do not belong to a subgroup which is conjugate a to free factor…

Group Theory · Mathematics 2010-11-04 Vladimir V. Yedynak

Given an isolated, quasi-homogeneous singularity $X$ we prove that there is a group isomorphism between the group of rank one reflexive sheaves on $X$ and the free abelian group generated by $\mathbb{C}^*$-divisors, modulo linear…

Algebraic Geometry · Mathematics 2023-01-13 Ananyo Dan , Agustín Romano-Velázquez

In this note, we give explicit examples of compact complex 3-folds which admit automorphisms that are isotopic to the identity through C $\infty$-diffeomorphisms but not through biholomorphisms. These automorphisms play an important role in…

Complex Variables · Mathematics 2017-04-12 Laurent Meersseman

The first part of this work uses the algorithm recently detailed in arXiv:1906.02935 to classify the irreducible weight modules of the minimal model vertex operator algebra $L_k(\mathfrak{sl}_3)$, when the level $k$ is admissible. These are…

Quantum Algebra · Mathematics 2022-10-19 Kazuya Kawasetsu , David Ridout , Simon Wood

We give elementary proofs of the following two theorems on automorphisms of a finite group G: (1) An automorphism of G is inner if and only if it extends to an automorphism of every finite group containing G. (2) There exists a finite…

Group Theory · Mathematics 2024-05-07 Benjamin Sambale