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Let X be an infinite compact metric space with finite covering dimension. Let $\afhpa,\bt: X\to X$ be two minimal homeomorphisms. Suppose that the range of $K_0$-groups of both crossed product C*-algebras s are dense in the space of real…

Operator Algebras · Mathematics 2007-05-23 Huaxin Lin

We classify all left-invariant pseudo-Riemannian Einstein metrics on $\mathrm{SL}(2,\mathbb{R})\times \mathrm{SL}(2,\mathbb{R})$ that are bi-invariant under a one-parameter subgroup. We find that there are precisely two such metrics up to…

Differential Geometry · Mathematics 2022-01-20 Vicente Cortés , Jeremias Ehlert , Alexander S. Haupt , David Lindemann

We prove that the commutator is stable in permutations endowed with the Hamming distance, that is, two permutations that almost commute are near two commuting permutations. Our result extends to $k$-tuples of almost commuting permutations,…

Group Theory · Mathematics 2016-08-08 Goulnara Arzhantseva , Liviu Paunescu

In this article, we construct semiparametrically efficient estimators of linear functionals of a probability measure in the presence of side information using an easy empirical likelihood approach. We use estimated constraint functions and…

Methodology · Statistics 2023-03-01 Shan Wang , Hanxiang Peng

We prove the existence of a quantum isometry groups for new classes of metric spaces: (i) geodesic metrics for compact connected Riemannian manifolds (possibly with boundary) and (ii) metric spaces admitting a uniformly distributed…

Quantum Algebra · Mathematics 2020-10-28 Alexandru Chirvasitu , Debashish Goswami

We show the existence of generalized clusters of a finite or even infinite number of sets, with minimal total perimeter and given total masses, in metric measure spaces homogeneous with respect to a group acting by measure preserving…

Analysis of PDEs · Mathematics 2021-12-16 Matteo Novaga , Emanuele Paolini , Eugene Stepanov , Vincenzo Maria Tortorelli

For an Alexandrov space (with curvature bounded below), we determine the maximal dimension of its isometry group and show that the space is isometric to a Riemannian manifold, provided the dimension of its isometry group is maximal. We also…

Differential Geometry · Mathematics 2014-02-26 Fernando Galaz-Garcia , Luis Guijarro

We define a distance analogous to the Gromov-Hausdorff distance that enables the comparison of arbitrary quasi-isometric spaces. We also investigate properties preserved under limits with respect to this distance, as well as properties of…

Metric Geometry · Mathematics 2026-05-28 Alexei Naianzin

We undertake a systematic study of the approximation properties of the topological and measurable versions of the coarse boundary groupoid associated to a sequence of finite graphs of bounded degree. On the topological side, we prove that…

Group Theory · Mathematics 2021-12-30 Vadim Alekseev , Leonardo Biz

This paper studies the multiplicative ideal structure of commutative rings in which every finitely generated ideal is quasi-projective. Section 2 provides some preliminaries on quasi-projective modules over commutative rings. Section 3…

Commutative Algebra · Mathematics 2016-01-29 J. Abuhlail , M. Jarrar , S. Kabbaj

We construct quasiconformal mappings in Euclidean spaces by integration of a discontinuous kernel against doubling measures with suitable decay. The differentials of mappings that arise in this way satisfy an isotropic form of the doubling…

Classical Analysis and ODEs · Mathematics 2007-09-03 Leonid V. Kovalev , Diego Maldonado , Jang-Mei Wu

We prove a relative isoperimetric inequality in the plane, when the perimeter is defined with respect to a convex, positively homogeneous function of degree one, and characterize the minimizers.

Analysis of PDEs · Mathematics 2014-01-28 Francesco Della Pietra , Nunzia Gavitone

We develop a version of Freiman's theorem for a class of non-abelian groups, which includes finite nilpotent, supersolvable and solvable A-groups. To do this we have to replace the small doubling hypothesis with a stronger relative…

Classical Analysis and ODEs · Mathematics 2012-12-04 Tom Sanders

We generalize the notion of isoperimetric profiles of finitely generated groups to their actions by measuring the boundary of finite subgraphings of the orbit graphing. We prove that like the classical isoperimetric profiles for groups,…

Dynamical Systems · Mathematics 2023-10-05 Zihan Xia

We study certain infinite-dimensional probability measures in connection with frame analysis. Earlier work on frame-measures has so far focused on the case of finite-dimensional frames. We point out that there are good reasons for a sharp…

Functional Analysis · Mathematics 2016-09-13 Palle E. T. Jorgensen , Myung-Sin Song

In this paper, we study the isotropy subgroups of some almost rigid domains and give necessary and sufficient conditions for an automorphism to be in the isotropy subgroup.

Commutative Algebra · Mathematics 2022-02-22 Nikhilesh Dasgupta , Animesh Lahiri

As part of a programme to classify quasi-Einstein metrics $(M,g,X)$ on closed manifolds and near-horizon geometries of extreme black holes, we study such spaces when the vector field $X$ is divergence-free but not identically zero. This…

Differential Geometry · Mathematics 2023-07-04 Eric Bahuaud , Sharmila Gunasekaran , Hari K Kunduri , Eric Woolgar

Two pseudo-Riemannian metrics are called projectively equivalent if their unparametrized geodesics coincide. The degree of mobility of a metric is the dimension of the space of metrics that are projectively equivalent to it. We give a…

Differential Geometry · Mathematics 2017-11-28 Vladimir S. Matveev , Stefan Rosemann

In this paper we classify countable locally finite-by-abelian groups up to coarse isomorphism. This classification is derived from a coarse classification of amenable shift-homogeneous metric spaces.

Metric Geometry · Mathematics 2014-12-16 Taras Banakh , Matija Cencelj , Dušan Repovš , Ihor Zarichnyi

Given a compactly supported probability measure on a Riemannian manifold, we study the asymptotic speed at which it can be approximated (in Wasserstein distance of any exponent p) by finitely supported measure. This question has been…

Optimization and Control · Mathematics 2012-07-17 Benoit Kloeckner