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Related papers: A note on ideal spaces of Mautner groups

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We discuss basic topological properties of unitary dual spaces of nilpotent Lie groups, using some ideas from operator algebras and their noncommutative dimension theory. The general results are illustrated by many examples.

Operator Algebras · Mathematics 2017-07-19 Ingrid Beltita , Daniel Beltita

We define the C^*-action on moduli spaces of reductive representations of fundamental groups of quasi-compact Kaehler manifolds by solving Hermitian-Yang-Mills equation. As applications in algebraic geometry we show a non-abelian Hodge…

Algebraic Geometry · Mathematics 2007-05-23 Juergen Jost , Jiayu Li , Kang Zuo

Given a Hausdorff locally compact \'etale groupoid $\mathcal G$, we describe as a topological space the part of the primitive spectrum of $C^*(\mathcal G)$ obtained by inducing one-dimensional representations of amenable isotropy groups of…

Operator Algebras · Mathematics 2025-03-05 Johannes Christensen , Sergey Neshveyev

We define a Riesz type interpolation property for the Cuntz semigroup of a $C^*$-algebra and prove it is satisfied by the Cuntz semigroup of every $C^*$-algebra with the ideal property. Related to this, we obtain two characterizations of…

Operator Algebras · Mathematics 2011-09-14 Cornel Pasnicu , Francesc Perera

We prove that if a connected and simply connected Lie group $G$ admits connected closed normal subgroups $G_1\subseteq G_2\subseteq \cdots \subseteq G_m=G$ with $\dim G_j=j$ for $j=1,\dots,m$, then its group $C^*$-algebra has closed…

Operator Algebras · Mathematics 2025-04-15 Ingrid Beltita , Daniel Beltita

We approach the quasi-isometric classification questions on Lie groups by considering low dimensional cases and isometries alongside quasi-isometries. First, we present some new results related to quasi-isometries between Heintze groups.…

Group Theory · Mathematics 2021-04-02 Ville Kivioja , Enrico Le Donne , Sebastiano Nicolussi Golo

Given an amenable second countable Hausdorff locally compact \'etale groupoid $\mathcal G$ such that each isotropy group $\mathcal G^x_x$ has local polynomial growth, we give a description of $\operatorname{Prim} C^*(\mathcal G)$ as a…

Operator Algebras · Mathematics 2025-07-16 Johannes Christensen , Sergey Neshveyev

Using the theory of Dixmier ideals developed in previous work, we show that every semiprime Lie ideal in a C*-algebra arises as the full normalizer subspace of a semiprime two-sided ideal. This leads to a concise description of all…

Operator Algebras · Mathematics 2025-11-05 Eusebio Gardella , Kan Kitamura , Hannes Thiel

The paper is concerned with defining a topology on the set of ideals of codimension d of the algebra C^\infty(M,R) with M being a compact smooth manifold. Its main property is that it is compact Hausdorff and it contains as a subspace the…

Differential Geometry · Mathematics 2010-06-23 Lukáš Vokřínek

The goal of this article is to investigate nontrivial $m$-quasi-Einstein manifolds globally conformal to an $n$-dimensional Euclidean space. By considering such manifolds, whose conformal factors and potential functions are invariant under…

Differential Geometry · Mathematics 2019-12-09 Ernani Ribeiro , Keti Tenenblat

Through the means of an alternative and less algebraic method, an explicit expression for the isometry groups of the six-dimensional homogeneous nearly K\"ahler manifolds is provided.

Differential Geometry · Mathematics 2024-11-11 Mateo Anarella , Michaël Liefsoens

Various questions on Lie ideals of C*-algebras are investigated. They fall roughly under the following topics: relation of Lie ideals to closed two-sided ideals; Lie ideals spanned by special classes of elements such as commutators,…

Operator Algebras · Mathematics 2015-09-25 Leonel Robert

In this paper, we provide a representation of a certain class of C*-valued positive sesquilinear and linear maps on non-unital quasi *-algebras. Also, we illustrate our results on the concrete examples of non-unital Banach quasi *-algebras,…

Operator Algebras · Mathematics 2024-09-10 Stefan Ivkovic , Bogdan D. Djordjevic , Giorgia Bellomonte

A countable group is C*-simple if its reduced C*-algebra is a simple algebra. Since Powers recognised in 1975 that non-abelian free groups are C*-simple, large classes of groups which appear naturally in geometry have been identified,…

Operator Algebras · Mathematics 2007-05-23 Pierre de la Harpe

In 1955 Dye proved that two von Neumann factors not of type I_2n are isomorphic (via a linear or a conjugate linear *-isomorphism) if and only if their unitary groups are isomorphic as abstract groups. We consider an analogue for…

Operator Algebras · Mathematics 2016-08-26 Thierry Giordano , Adam Sierakowski

Fr\"olicher spaces form a cartesian closed category which contains the category of smooth manifolds as a full subcategory. Therefore, mapping groups such as C^\infty(M,G) or \Diff(M), but also projective limits of Lie groups are in a…

Differential Geometry · Mathematics 2009-06-25 Martin Laubinger

We investigate the ideal structures of the C^*-algebras arising from topological graphs. We give the complete description of ideals of such C^*-algebras which are invariant under the so-called gauge action, and give the condition on…

Operator Algebras · Mathematics 2007-05-23 Takeshi Katsura

We give a classification, up to local isomorphisms, of semi-simple Lie groups without compact factors that can act faithfully and conformally on a compact Lorentz manifold of dimension greater than or equal to $3$.

Differential Geometry · Mathematics 2015-06-30 Vincent Pecastaing

In this paper, we study a subclass of the class of MD-algebras, i.e., the class of solvable real Lie algebras such that the K-orbits of its corresponding connected and simply connected Lie groups are either orbits of dimension zero or…

Rings and Algebras · Mathematics 2008-02-18 Le Anh Vu , Kar Ping Shum

We show, by an elementary and explicit construction, that the group of Hamiltonian diffeomorphisms of certain symplectic manifolds, endowed with Hofer's metric, contains subgroups quasi-isometric to Euclidean spaces of arbitrary dimension.

Differential Geometry · Mathematics 2008-09-09 Pierre Py