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Related papers: Decomposing diffeomorphisms of the sphere

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It was shown by Ramanathan \cite{R} that any compact oriented non-simply-connected minimal surface in the three-dimensional round sphere admits at most a finite set of pairwise noncongruent minimal isometric immersions. Here we show that…

Differential Geometry · Mathematics 2015-07-15 M. Dajczer , Th. Vlachos

We study the decomposability of Specht modules labelled by bihooks, bipartitions with a hook in each component, for the Iwahori--Hecke algebra of type $B$. In all characteristics, we determine a large family of decomposable Specht modules,…

Representation Theory · Mathematics 2020-02-12 Liron Speyer , Louise Sutton

In this article, we characterize the distortion elements of the group of smooth diffeomorphisms of the circle and of the group of compactly supported smooth diffeomorphisms of the real line. More precisely, we prove that, in this context,…

Dynamical Systems · Mathematics 2025-07-21 Hélène Eynard-Bontemps , Emmanuel Militon

Some new differentiable sphere theorems are obtained via the Ricci flow and stable currents. We prove that if $M^n$ is a compact manifold whose normalized scalar curvature and sectional curvature satisfy the pointwise pinching condition…

Differential Geometry · Mathematics 2011-02-14 Juan-Ru Gu , Hong-Wei Xu

We prove that the group of Hamiltonian diffeomorphisms of the 2-sphere has infinite diameter with respect to Hofer's metric. Our approach is based on the theory of Lagrangian intersections.

Differential Geometry · Mathematics 2007-05-23 Leonid Polterovich

We explain how the round four-sphere can be sliced along homogeneous 3~-~manifolds of topology $S^3/D_8^*$. This defines a Euclidean Bianchi type IX model for Einstein's equations with cosmological constant. The geometric properties of this…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Domenico Giulini

We provide the full classification of equidistant decomposition of a two-dimensional Euclidean plane and a two-dimensional sphere.

Differential Geometry · Mathematics 2026-05-20 Darya Sukhorebska

We study the space of Riemannian metrics over a compact manifold equipped with the Ebin metric. We characterize its self-isometries and prove that two such spaces are isometric if and only if their underlying manifolds are diffeomorphic.

Metric Geometry · Mathematics 2025-12-09 David Lenze

Let $G$ be a usc decomposition of $S^n$, $H_G$ denote the set of nondegenerate elements and $\pi$ be the natural projection of $S^n$ onto $S^n/G$. Suppose that each point in the decomposition space has arbitrarily small neighborhoods with…

Geometric Topology · Mathematics 2013-12-05 Shijie Gu

We state that any constant curvature Riemannian metric with conical singularities of constant sign curvature on a compact (orientable) surface $S$ can be realized as a convex polyhedron in a Riemannian or Lorentzian) space-form. Moreover…

Differential Geometry · Mathematics 2010-11-16 François Fillastre

In this letter, first we give a decomposition for any Lie-Poisson structure $\pi_g$ associated to the modular vector. In particular, $\pi_g$ splits into two compatible Lie-Poisson structures if $dim{g} \leq 3$. As an application, we…

Differential Geometry · Mathematics 2015-05-13 Qian Lin , Zhangju Liu , Yunhe Sheng

We prove unobstructed deformations for compact Kaehlerian even-dimensional Poisson manifolds whose Poisson tensor degenerates along a divisor with mild singularities. Examples include Hilbert schemes of del Pezzo surfaces.

Algebraic Geometry · Mathematics 2016-09-21 Ziv Ran

We present in this paper new multiscale transforms on the sphere, namely the isotropic undecimated wavelet transform, the pyramidal wavelet transform, the ridgelet transform and the curvelet transform. All of these transforms can be…

Astrophysics · Physics 2016-08-30 Jean-Luc Starck , Yassir Moudden , Pierrick Abrial , Mai Nguyen

We construct flat metrics in a given conformal class with prescribed singularities of real orders at marked points of a closed real surface. The singularities can be small conical, cylindrical, and large conical with possible translation…

Differential Geometry · Mathematics 2011-01-13 Sergiu Moroianu

We prove that any minimal Lagrangian diffeomorphism between two closed spherical surfaces with cone singularities is an isometry, without any assumption on the multiangles of the two surfaces. As an application, we show that every branched…

Differential Geometry · Mathematics 2024-10-25 Christian El Emam , Andrea Seppi

An unobstructedness theorem is proved for deformations of compact holomorphic Poisson manifolds and applied to a class of examples. These include certain rational surfaces and Hilbert schemes of points on Poisson surfaces. We study in…

Differential Geometry · Mathematics 2011-05-25 Nigel Hitchin

The sphericalization procedure converts a Euclidean space into a compact sphere. In this note we propose a variant of this procedure for locally compact, rectifiably path-connected, non-complete, unbounded metric spaces by using conformal…

Metric Geometry · Mathematics 2022-08-22 Ryan Gibara , Nageswari Shanmugalingam

We give a sketch of proof that any two (Lebesgue) measurable subsets of the unit sphere in $R^n$, for $n\ge 3$, with non-empty interiors and of the same measure are equidecomposable using pieces that are measurable.

Metric Geometry · Mathematics 2014-08-12 Łukasz Grabowski , András Máthé , Oleg Pikhurko

The two main topics of this text are as follows: Firstly, three modifications of the theorem of Beltrami will be presented for diffeomorphisms between Riemannian manifolds and a space form which preserve the geodesic circles, the geodesic…

Differential Geometry · Mathematics 2009-12-22 Steven Verpoort

We give the following characterization of rectifiable metric spaces. A metric space with positive lower Hausdorff density is rectifiable if and only if, for any subset $F$ and $f:F\to Y$, a Lipschitz map into a metric space with positive…

Metric Geometry · Mathematics 2025-10-16 Sean Li , Raanan Schul