English
Related papers

Related papers: A compact group which is not Valdivia compact

200 papers

Let $(W,S)$ be a Coxeter system with Davis complex $\Sigma$. The polyhedral automorphism group $G$ of $\Sigma$ is a locally compact group under the compact-open topology. If $G$ is a discrete group (as characterised by Haglund--Paulin),…

Group Theory · Mathematics 2015-12-01 Damian Sercombe

Wreath products of non-discrete locally compact groups are usually not locally compact groups, nor even topological groups. We introduce a natural extension of the wreath product construction to the setting of locally compact groups. As an…

Group Theory · Mathematics 2019-07-10 Yves Cornulier

Totally complex submanifolds of a quaternionic K\"{a}hler manifold are analogous to complex submanifolds of a K\"{a}hler manifold. In this paper, we construct an example of a non-compact totally complex submanifold of maximal dimension of a…

Differential Geometry · Mathematics 2025-04-16 Yuuki Sasaki

\emph{Scalable spaces} are simply connected compact manifolds or finite complexes whose real cohomology algebra embeds in their algebra of (flat) differential forms. This is a rational homotopy invariant property and all scalable spaces are…

Geometric Topology · Mathematics 2022-09-16 Aleksandr Berdnikov , Fedor Manin

Given a Lie group $G$ with finitely many components and a compact Lie group A which acts on $G$ by automorphisms, we prove that there always exists an A-invariant maximal compact subgroup K of G, and that for every such K, the natural map…

Group Theory · Mathematics 2009-04-21 Jinpeng An , Ming Liu , Zhengdong Wang

If G is a locally essential subgroup of a compact abelian group K, then: (i) t(G)=w(G)=w(K), where t(G) is the tightness of G; (ii) if G is radial, then K must be metrizable; (iii) G contains a super-sequence S converging to 0 such that…

General Topology · Mathematics 2019-11-12 Dikran Dikranjan , Dmitri Shakhmatov

We prove a compactness theorem for metrics with Bounded Integral Curvature on a fixed closed surface $\Sigma$. As a corollary, we obtain a compactification of the space of Riemannian metrics with conical singularities, where an accumulation…

Differential Geometry · Mathematics 2016-10-20 Clément Debin

For a classical weight function $\rho$ defined on a simply connected open subset $\Omega$ of $\mathbb{R}^2$ (either bounded or unbounded) with piecewise $C^1$ boundary, we prove density and compact embedding of a matrix-weighted Sobolev…

Classical Analysis and ODEs · Mathematics 2026-05-26 M. K. Nangho , B. J. Nkwamouo , J. L. Woukeng

We show that any group $G$ is contained in some sharply 2-transitive group $\mathcal{G}$ without a non-trivial abelian normal subgroup. This answers a long-standing open question. The involutions in the groups $\mathcal{G}$ that we…

Group Theory · Mathematics 2015-05-29 Eliyahu Rips , Yoav Segev , Katrin Tent

In this paper we develop a theory of convexity for a free Abelian group M (the lattice of integer points), which we call theory of discrete convexity. We characterize those subsets X of the group M that could be call "convex". One property…

Combinatorics · Mathematics 2007-05-23 V. I. Danilov , G. A. Koshevoy

Let $G$ be a connected, simply-connected, compact simple Lie group. In this paper, we show that the isometry group of $G$ with a left-invariant pseudo-Riemannan metric is compact. Furthermore, the identity component of the isometry group is…

Differential Geometry · Mathematics 2020-03-03 Zhu Fuhai , Chen Zhiqi , Liang Ke

We show that every locally compact strictly convex metric group is abelian, thus answering one problem posed by the authors in their earlir paper. To prove this theorem we first construct the isomorphic embeddings of the real line into the…

Group Theory · Mathematics 2025-10-14 Taras Banakh , Oles Mazurenko

Let V be a finite dimensional real Euclidean Jordan algebra with the identity element 1. Let Q be the closed convex cone of squares. We show that the Wiener- Hopf compactification of Q is the interval (1-Q) \cap (-1+Q). As a consequence, we…

Operator Algebras · Mathematics 2016-06-13 S. Sundar

This article discusses the existence problem of a compact quotient of a symmetric space by a properly discontinuous group with emphasis on the non-Riemannian case. Discontinuous groups are not always abundant in a homogeneous space $G/H$ if…

Differential Geometry · Mathematics 2011-06-22 Toshiyuki Kobayashi , Taro Yoshino

We prove that the existence of a selective ultrafilter implies the existence of a countably compact Hausdorff group topology on the free Abelian group of size continuum. As a consequence, we show that the existence of a selective…

General Topology · Mathematics 2020-06-25 A. C. Boero , I. Castro-Pereira , A. H. Tomita

We extend the definition of Bockstein basis $\sigma(G)$ to nilpotent groups $G$. A metrizable space $X$ is called a {\it Bockstein space} if $\dim_G(X) = \sup\{\dim_H(X) | H\in \sigma(G)\}$ for all Abelian groups $G$. Bockstein First…

Geometric Topology · Mathematics 2019-11-18 M. Cencelj , J. Dydak , A. Mitra , A. Vavpetic

Let Wh^w(G) be the K_1-group of square matrices over the integral group ring ZG which are not necessarily invertible but induce weak isomorphisms after passing to Hilbert space completions. Let D(G) be the division closure of ZG in the…

K-Theory and Homology · Mathematics 2018-03-16 Peter Linnell , Wolfgang Lück

Our paper begins with a revision of spectral theory for commutative Banach algebras, which enables us to prove the $L^p_{\omega}-$conjecture for locally compact abelian groups. We follow an alternative approach to the one known in the…

Functional Analysis · Mathematics 2017-10-25 Mateusz Krukowski

We construct a combinatorial moduli space closely related to the KSV-compactification of the moduli space of bordered marked Riemann surfaces. The open part arises from symmetric metric ribbon graphs. The compactification is obtained by…

Geometric Topology · Mathematics 2023-10-03 Ralph Kaufmann , Javier Zúñiga

For every convex disk $K$ (a convex compact subset of the plane, with non-void interior), the packing density $\delta(K)$ and covering density $\vartheta(K)$ form an ordered pair of real numbers, {\em i.e.}, a point in ${\mathbb R}^2$. The…

Metric Geometry · Mathematics 2013-09-03 Włodzimierz Kuperberg