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Related papers: The type I dichotomy for two-step nilpotent locall…

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We use the structure lattice, introduced in Part I, to undertake a systematic study of the class $\mathscr S$ consisting of compactly generated, topologically simple, totally disconnected locally compact groups that are non-discrete. Given…

Group Theory · Mathematics 2017-07-07 Pierre-Emmanuel Caprace , Colin D. Reid , George A. Willis

The authors have shown previously that every locally pro-p contraction group decomposes into the direct product of a p-adic analytic factor and a torsion factor. It has long been known that p-adic analytic contraction groups are nilpotent.…

Group Theory · Mathematics 2020-08-11 Helge Glockner , George A. Willis

The 'degree of k-step nilpotence' of a finite group G is the proportion of the tuples (x_1,...,x_{k+1}) in G^{k+1} for which the simple commutator [x_1,...,x_{k+1}] is equal to the identity. In this paper we study versions of this for an…

Group Theory · Mathematics 2025-12-04 Armando Martino , Matthew Tointon , Motiejus Valiunas , Enric Ventura

We obtain many results and solve some problems about feebly compact paratopological groups. We obtain necessary and sufficient conditions for such a group to be topological. One of them is the quasiregularity. We prove that each…

Group Theory · Mathematics 2020-08-05 Taras Banakh , Alex Ravsky

We study the topology of orbits of dynamical systems defined by finite-dimensional representations of nilpotent Lie groups. Thus, the following dichotomy is established: either the interior of the set of regular points is dense in the…

Operator Algebras · Mathematics 2021-07-28 Ingrid Beltita , Daniel Beltita

In the present paper we study the rigidity of 2-step Carnot groups, or equivalently, of graded 2-step nilpotent Lie algebras. We prove the alternative that depending on bi-dimensions of the algebra, the Lie algebra structure makes it either…

Representation Theory · Mathematics 2017-05-23 Mauricio Godoy Molina , Boris Kruglikov , Irina Markina , Alexander Vasil'ev

We show that torsion-free finitely generated nilpotent groups are characterised by their group C*-algebras and we additionally recover their nilpotency class as well as the subquotients of the upper central series. We then use a C*-bundle…

Operator Algebras · Mathematics 2018-08-31 Caleb Eckhardt , Sven Raum

We study locally compact groups having all dense subgroups (locally) minimal. We call such groups densely (locally) minimal. In 1972 Prodanov proved that the infinite compact abelian groups having all subgroups minimal are precisely the…

General Topology · Mathematics 2018-08-24 Wenfei Xi , Dikran Dikranjan , Menachem Shlossberg , Daniele Toller

Every finite dimensional real representation of a compact real semisimple Lie algebra determines a metric 2-step nilpotent Lie algebra and a corresponding simply connected metric 2-step nilpotent Lie group N. We study the differential…

Differential Geometry · Mathematics 2008-06-18 Patrick Eberlein

We classify compactly generated locally compact groups of polynomial growth up to $L^p$ measure equivalence (ME) for all $p\leq 1$. To achieve this, we combine rigidity results (previously proved for discrete groups by Bowen and Austin)…

Group Theory · Mathematics 2025-05-26 Thiebout Delabie , Claudio Llosa Isenrich , Romain Tessera

We give a characterization of the $2$-step nilpotent Lie algebras whose corresponding Lie groups admit a left invariant complex structure. This is done by considering separately the cases when the complex structure is 2-step or 3-step…

Differential Geometry · Mathematics 2025-08-11 Maria Laura Barberis

In this paper we study contact structure on 2-step nilpotent, Heisenberg type Lie groups. We decompose this Lie groups to center and orthogonal complement, then investigate properties of both orthogonal Lie subgroups. Finally, we provide a…

Differential Geometry · Mathematics 2017-06-12 Babak Hasanzadeh

We prove that the relative K-groups associated with a nilpotent extension of Z/p^N Z-algebras and the bi-relative K-groups associated with a Milnor square of Z/p^N Z-algebras are p-primary torsion groups of bounded exponent. We also show…

K-Theory and Homology · Mathematics 2015-03-27 Thomas Geisser , Lars Hesselholt

We define a class of Riemannian and pseudo-Riemannian 2-step nilpotent Lie groups with nondegenerate centers that generalize the H-type groups of Kaplan. Examples are given and geometric properties are investigated.

Differential Geometry · Mathematics 2021-08-05 Justin M. Ryan

We conjecture that the "nilpotent points" of Calogero-Moser space for reflection groups are parametrised naturally by the two-sided cells of the group with unequal parameters. The nilpotent points correspond to blocks of restricted…

Representation Theory · Mathematics 2007-05-23 I. G. Gordon , M. Martino

It is shown that each non-compact locally compact second countable non-(T) group $G$ possesses non-strongly ergodic weakly mixing IDPFT Poisson actions of arbitrary Krieger's type. These actions are amenable if and only if $G$ is amenable.…

Dynamical Systems · Mathematics 2022-06-14 Alexandre I. Danilenko

We consider expansive group actions on a compact metric space containing a special fixed point denoted by $0$, and endomorphisms of such systems whose forward trajectories are attracted toward $0$. Such endomorphisms are called…

Dynamical Systems · Mathematics 2019-02-18 Ville Salo , Ilkka Törmä

The Addition Theorem for the algebraic entropy of group endomorphisms of torsion abelian groups was proved in [4]. Later, this result was extended to all abelian groups [3] and, recently, to all torsion finitely quasihamiltonian groups [7].…

Group Theory · Mathematics 2022-09-13 Menachem Shlossberg

We establish new results on the weak containment of quasi-regular and Koopman representations of a second countable locally compact group $G$ associated with non-singular $G$-spaces. We deduce that any two boundary representations of a…

Group Theory · Mathematics 2022-02-15 Pierre-Emmanuel Caprace , Mehrdad Kalantar , Nicolas Monod

We present a simple and intuitive framework for duality of locally compacts groups, which is not based on the Haar measure. This is a map, functorial on a non-degenerate subcategory, on the category of coinvolutive Hopf \cst-algebras, and a…

Operator Algebras · Mathematics 2021-04-09 Yulia Kuznetsova