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For profinite branch groups, we first demonstrate the equivalence of the Bergman property, uncountable cofinality, Cayley boundedness, the countable index property, and the condition that every non-trivial normal subgroup is open; compact…

Group Theory · Mathematics 2016-02-02 François Le Maître , Phillip Wesolek

We settle an old conjecture of Karrass and Solitar by proving that a finitely generated subgroup of a non-trivial free product $G = A\ast B$ has finite index if and only if it intersects non-trivially each non-trivial normal subgroup of…

Group Theory · Mathematics 2013-11-08 Benjamin Steinberg

In the hyperalgebra of the $r$-th Frobenius kernel of a universal Chevalley group over a field of characteristic $p>0$, we study some subsets and the subalgebras generated by them and give some results. We are particularly interested in the…

Rings and Algebras · Mathematics 2023-11-14 Yutaka Yoshii

A profinite group equipped with an expansive endomorphism is equivalent to a one-sided group shift. We show that these groups have a very restricted structure. More precisely, we show that any such group can be decomposed into a finite…

Dynamical Systems · Mathematics 2020-08-04 Michael Wibmer

We classify, up to isomorphism, all gradings by an arbitrary abelian group on simple finitary Lie algebras of linear transformations (special linear, orthogonal and symplectic) on infinite-dimensional vector spaces over an algebraically…

Rings and Algebras · Mathematics 2012-12-04 Yuri Bahturin , Matej Brešar , Mikhail Kochetov

We prove that a finitely generated group contains a sequence of non-trivial elements which converge to the identity in every compact homomorphic image if and only if the group is not virtually abelian.

Group Theory · Mathematics 2019-08-15 Andreas Thom

In "Almost Free Modules, Set-theoretic Methods", Eklof and Mekler raised the question about the existence of dual abelian groups G which are not isomorphic to Z+G. Recall that G is a dual group if G ~ D^* for some group D with D^*=Hom(D,Z).…

Logic · Mathematics 2007-05-23 Ruediger Goebel , Saharon Shelah

For a variety of finite groups $\mathbf H$, let $\overline{\mathbf H}$ denote the variety of finite semigroups all of whose subgroups lie in $\mathbf H$. We give a characterization of the subsets of a finite semigroup that are pointlike…

Group Theory · Mathematics 2018-01-16 Samuel J. v. Gool , B. Steinberg

In this paper, we show existence and uniqueness of a solution to a functional differential equation with infinite delay. We choose an appropriate Frechet space so as to cover a large class of functions to be used as initial functions to…

Dynamical Systems · Mathematics 2007-07-17 T Sengadir

Inverse semigroups are a class of semigroups whose structure induces a compatible partial order. This partial order is examined so as to establish mirror properties between an inverse semigroup and the semilattice of its idempotent…

Rings and Algebras · Mathematics 2013-01-25 Paul Poncet

We show that contracting self-similar groups satisfy the Farrell-Jones conjectures as soon as their universal contracting cover is non-positively curved. This applies in particular to bounded self-similar groups. We define, along the way, a…

K-Theory and Homology · Mathematics 2015-01-29 Laurent Bartholdi

Here we show that a finite nilpotent group is 2-closed if and only if it is either cyclic or a direct product of a generalized quaternion group with a cyclic group of odd order.

Group Theory · Mathematics 2017-05-18 Alireza Abdollahi , Majid Arezoomand

A group $G$ is invariably generated (IG) if there is a subset $S \subseteq G$ such that for every subset $S' \subseteq G$, obtained from $S$ by replacing each element with a conjugate, $S'$ generates $G$. $G$ is finitely invariably…

Group Theory · Mathematics 2022-07-08 Ashot Minasyan

Let $F$ be a field with characteristic $\neq 2$. We show that $F$ is a nonrigid field if and only if certain small 2-groups occur as Galois groups over $F$. These results provide new "automatic realizability" results for Galois groups over…

Number Theory · Mathematics 2007-05-23 Wenfeng Gao , David B. Leep , Jan Minac , Tara L. Smith

We consider the relationship between two sufficient conditions for regularity of the Bergman Projection on smooth, bounded, pseudoconvex domains. We show that if the set of infinite type points is reasonably well-behaved, then the existence…

Complex Variables · Mathematics 2018-01-24 Phillip S. Harrington

Let $f:X\to X $ be a dominant self-morphism of an algebraic variety over an algebraically closed field of characteristic zero. We consider the set $\Sigma_{f^{\infty}}$ of $f$-periodic (irreducible closed) subvarieties of small dynamical…

Algebraic Geometry · Mathematics 2022-08-10 Yohsuke Matsuzawa , Sheng Meng , Takahiro Shibata , De-Qi Zhang , Guolei Zhong

In [13], it is proved that any subgroup of $\mathrm{Diff}_{+}^{\omega }(I)$ (the group of orientation preserving analytic diffeomorphisms of the interval) is either metaabelian or does not satisfy a law. A stronger question is asked whether…

Group Theory · Mathematics 2025-06-10 Azer Akhmedov

Let G be the homeomorphism group of a dendrite. We study the normal subgroups of G. For instance, there are uncountably many non-isomorphic such groups G that are simple groups. Moreover, these groups can be chosen so that any isometric…

Group Theory · Mathematics 2021-02-03 Bruno Duchesne , Nicolas Monod

We prove that if $F$ is a finitely generated abelian group of orientation preserving $C^1$ diffeomorphisms of $R^2$ which leaves invariant a compact set then there is a common fixed point for all elements of $F.$ We also show that if $F$ is…

Dynamical Systems · Mathematics 2007-05-23 John Franks , Michael Handel , Kamlesh Parwani

An integral domain $D$ is called a finite factorization domain (FFD) if every nonzero nonunit element of $D$ has only finitely many non-associate divisors. In 1998, for an integral domain $D$ and a cancellative torsion-free monoid $S$ such…

Commutative Algebra · Mathematics 2025-06-16 Mohamed Benelmekki