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Related papers: On co-Hopfian nilpotent groups

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We investigate the commuting automorphisms of nilpotent Lie algebras $L$ with coclass $\leq 3$. Our examination exposes the conditions under which the set of commuting automorphisms of $L$ forms a subgroup within its automorphism group.

Rings and Algebras · Mathematics 2024-04-22 Shushma Rani , Niranjan Nehra , Rohit Garg

We classify all finite-dimensional connected Hopf algebras with large abelian primitive spaces. We show that they are Hopf algebra extensions of restricted enveloping algebras of certain restricted Lie algebras. For any abelian matched pair…

Rings and Algebras · Mathematics 2015-07-02 Xingting Wang

Two groups are said to have the same nilpotent genus if they have the same nilpotent quotients. We answer four questions of Baumslag concerning nilpotent completions. (i) There exists a pair of finitely generated, residually…

Group Theory · Mathematics 2015-01-08 Martin R. Bridson , Alan W. Reid

We show that certain cyclically pinched one-relator groups are residually torsion-free nilpotent.

Group Theory · Mathematics 2015-03-18 John Labute

In this survey, we study representations of finitely generated groups into Lie groups, focusing on the deformation spaces of convex real projective structures on closed manifolds and orbifolds, with an excursion on projective structures on…

Geometric Topology · Mathematics 2016-12-02 Suhyoung Choi , Gye-Seon Lee , Ludovic Marquis

We provide an explicit construction for a complete set of orthogonal primitive idempotents of finite group algebras over nilpotent groups. Furthermore, we give a complete set of matrix units in each simple epimorphic image of a finite group…

Representation Theory · Mathematics 2013-02-19 Inneke Van Gelder , Gabriela Olteanu

We develop nilpotently $p$-localization of knot groups in terms of the (symplectic) automorphism groups of free nilpotent groups. We show that any map from the set of conjugacy classes of the outer automorphism groups yields a knot…

Geometric Topology · Mathematics 2026-01-16 Takefumi Nosaka

We consider the so-called {\it strongly co-Hopfian} and {\it uniformly strongly co-Hopfian} Abelian groups, significantly generalizing some important results due to Abdelalim in the J. Math. Analysis (2015). Specifically, we prove that any…

Group Theory · Mathematics 2025-12-01 Andrey R. Chekhlov , Peter V. Danchev , Patrick W. Keef

We describe the structure of "K-approximate subgroups'' of solvable subgroups of GL_n(C), showing that they have a large nilpotent piece. By combining this with the main result of our recent paper on approximate subgroups of torsion-free…

Group Theory · Mathematics 2009-07-07 Emmanuel Breuillard , Ben Green

We show that if a countably generated Lie algebra $H$ does not contain isomorphic copies of certain finite-dimensional nilpotent Lie algebras $A$ and $B$ (satisfying some mild conditions), then $H$ embeds into a quotient of $A \ast B$ that…

Rings and Algebras · Mathematics 2023-10-20 Luis Mendonça

A group G is (finitely) co-Hopfian if it does not contain any proper (finite-index) subgroups isomorphic to itself. We study finitely generated groups G that admit a descending chain of proper normal finite-index subgroups, each of which is…

Group Theory · Mathematics 2020-12-24 Wouter van Limbeek

We establish vanishing results for the first cohomology group of nilpotent groups and Lie rings when the submodule of invariants is trivial. Our results are obtained within a model-theoretic setting, namely for structures that are definable…

Logic · Mathematics 2026-04-07 Samuel Zamour

In this paper, we investigate the existence of fixed-point-free automorphisms for finite-dimensional Lie algebras. By a result of Jacobson, a Lie algebra admitting a fixed-point-free automorphism is solvable. We prove that such a Lie…

Rings and Algebras · Mathematics 2026-05-01 Dietrich Burde , Karel Dekimpe

The pro-isomorphic zeta function of a torsion-free finitely generated nilpotent group G enumerates finite index subgroups H such that H and G have isomorphic profinite completions. It admits an Euler product decomposition, indexed by the…

Group Theory · Mathematics 2014-08-29 Mark N. Berman , Benjamin Klopsch

We construct finitely generated simple torsion-free groups with strong homological control. Our main result is that every subset of $\mathbb{N} \cup \{\infty\}$, with some obvious exceptions, can be realized as the set of dimensions of…

Group Theory · Mathematics 2025-04-14 Francesco Fournier-Facio , Bin Sun

We show that if a torsion free nilpotent group $G$ has a balanced presentations and Hirsch length $h(G)>3$ then $\beta_1(G;\mathbb{Q})=2$. There is just one such group which is torsion-free and of Hirsch length $h=4$, and none with $h=5$.…

Group Theory · Mathematics 2026-05-14 J. A. Hillman

A connected Lie group admitting an expansive automorphism is known to be nilpotent, but all nilpotent Lie groups do not admit expansive automorphism. In this article, we find sufficient conditions for a class of nilpotent Lie groups to…

Group Theory · Mathematics 2019-09-10 Manoj Choudhuri , C. R. E. Raja

In this article character groups of Hopf algebras are studied from the perspective of infinite-dimensional Lie theory. For a graded and connected Hopf algebra we construct an infinite-dimensional Lie group structure on the character group…

Group Theory · Mathematics 2016-08-08 Geir Bogfjellmo , Rafael Dahmen , Alexander Schmeding

We combine classical methods of combinatorial group theory with the theory of small cancellations over relatively hyperbolic groups to construct finitely generated torsion-free groups that have only finitely many classes of conjugate…

Group Theory · Mathematics 2009-07-07 Ashot Minasyan

It is proved that for any prime $p$ a finitely generated nilpotent group is conjugacy separable in the class of finite $p$-groups if and only if the torsion subgroup of it is a finite $p$-group and the quotient group by the torsion subgroup…

Group Theory · Mathematics 2007-05-23 E. A. Ivanova