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Related papers: Sobolev mappings between nonrigid Carnot groups

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This is the first in a series of papers on geometric mapping theory in Carnot groups -- and more generally equiregular manifolds -- in which we prove a number of new structural results for Sobolev (in particular quasisymmetric) mappings,…

Differential Geometry · Mathematics 2021-12-21 Bruce Kleiner , Stefan Muller , Xiangdong Xie

We study the pullback theorem of Sobolev mappings on Carnot groups via mollification of mappings. With the pullback theorem we extend the classical result proved by Xiangdong Xie : Rigidity of Sobolev mappings $W^{1,p}(G_1;G_2)$ for…

Metric Geometry · Mathematics 2026-02-03 Yihan Cui

Let $N\subset GL(n,R)$ be the group of upper triangular matrices with $1$s on the diagonal, equipped with the standard Carnot group structure. We show that quasiconformal homeomorphisms between open subsets of $N$, and more generally…

Differential Geometry · Mathematics 2022-08-02 Bruce Kleiner , Stefan Muller , Xiangdong Xie

In the article we study mappings of Carnot groups satisfy moduli inequalities. We prove that homeomorphisms satisfy the moduli inequalities ($Q$-homeomor\-phisms) with a locally integrable function $Q$ are Sobolev mappings. On this base in…

Analysis of PDEs · Mathematics 2020-04-20 Evgenii Sevost'yanov , Alexander Ukhlov

We study quasiconformal maps on non-rigid Carnot groups equipped with Carnot metric. We show that for most non-rigid Carnot groups N, all quasiconformal maps on N must be biLipschitz.

Complex Variables · Mathematics 2013-08-15 Xiangdong Xie

We provide a new geometric proof of Reimann's theorem characterizing quasiconformal mappings as the ones preserving functions of bounded mean oscillation. While our proof is new already in the Euclidean spaces, it is applicable in…

Classical Analysis and ODEs · Mathematics 2016-03-16 Riikka Korte , Niko Marola , Olli Saari

We show that quasiconformal maps on many Carnot groups must be biLipschitz. In particular, this is the case for 2-step Carnot groups with reducible first layer. These results have implications for the rigidity of quasiisometries between…

Complex Variables · Mathematics 2016-06-15 Xiangdong Xie

We study mappings on sub-Riemannian manifolds which are quasi-regular with respect to the Carnot-Caratheodory distances and discuss several related notions. On H-type Carnot groups, quasiregular mappings have been introduced earlier using…

Metric Geometry · Mathematics 2016-06-21 Katrin Fassler , Anton Lukyanenko , Kirsi Peltonen

In this paper, we prove the commutativity between the Pansu pullback of a smooth contact map between Carnot groups and the differentials appearing in the spectral complexes. As a direct application, we also present a way of "lifting" a…

Differential Geometry · Mathematics 2026-03-24 Filippa Lo Biundo , Francesca Tripaldi

In this paper we show that if $Y=N \times \mathbb{Q}_m$ is a metric space where $N$ is a Carnot group endowed with the Carnot-Caratheodory metric then any quasisymmetric map of $Y$ is actually bilipschitz. The key observation is that $Y$ is…

Group Theory · Mathematics 2014-04-22 Tullia Dymarz

We prove several rigidity properties for random quotients of mapping class groups of surfaces, namely whose kernel is normally generated by the n-th steps of finitely many independent random walks. Firstly, we generalise a celebrated…

Group Theory · Mathematics 2025-08-18 Giorgio Mangioni

We show that fiber-preserving quasisymmetric maps are biLipschitz. As an application, we show that quasisymmetric maps on Carnot groups with reducible first stratum are biLipschitz.

Metric Geometry · Mathematics 2015-01-13 Enrico Le Donne , Xiangdong Xie

We describe all quasiconformal maps on the higher (real and complex) model Filiform groups equipped with the Carnot metric, including non-smooth ones. These maps have very special forms. In particular, they are all biLipschitz and preserve…

Complex Variables · Mathematics 2013-08-15 Xiangdong Xie

We prove a rigidity theorem for the Poisson automorphisms of the function fields of tori with quadratic Poisson structures over fields of characteristic 0. It gives an effective method for classifying the full Poisson automorphism groups of…

Rings and Algebras · Mathematics 2016-09-23 Jesse Levitt , Milen Yakimov

A quasihomomorphism is a map that satisfies the homomorphism relation up to bounded error. Fujiwara and Kapovich proved a rigidity result for quasihomomorphisms taking values in discrete groups, showing that all quasihomomorphisms can be…

Group Theory · Mathematics 2026-03-04 Sami Douba , Francesco Fournier-Facio , Sam Hughes , Simon Machado

Let $M$ be a smooth compact oriented connected manifold, and ${\rm Homeo}_0(M,\mu)$ the group of homeomorphisms of $M$ supported away from $\partial M,$ which preserve a Borel probability measure $\mu$ induced by a volume form on $M$, and…

Geometric Topology · Mathematics 2026-05-06 Michael Brandenbursky , Jarek Kedra , Michal Marcinkowski , Egor Shelukhin

We show that the tangent cone at the identity is not a complete quasiconformal invariant for sub-Riemannian nilpotent groups. Namely, we show that there exists a nilpotent Lie group equipped with left invariant sub-Riemannian metric that is…

Metric Geometry · Mathematics 2013-12-24 Enrico Le Donne , Alessandro Ottazzi , Ben Warhurst

We characterize the rigidity of Carnot groups in the class of $C^2$ contact maps in terms of complex characteristics. Furthermore, we obtain a Liouville type theorem for Carnot groups which states that 1-quasiconformal maps form finite…

Differential Geometry · Mathematics 2010-07-09 A. Ottazzi , B. Warhurst

Among connected linear algebraic groups, quasi-reductive groups generalize pseudo-reductive groups, which in turn form a useful relaxation of the notion of reductivity. We study quasi-reductive groups over non-archimedean local fields,…

Group Theory · Mathematics 2019-01-28 Maarten Solleveld

The paper deals with quasigroups having a trivial group of automorphisms and a trivial group of autotopisms. Examples of such quasigroups and methods of their verification are given.

Group Theory · Mathematics 2009-05-26 Andriy I. Deriyenko , Ivan I. Deriyenko , Wieslaw A. Dudek
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