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Constructing equivariant maps for representations

Stefano Francaviglia (2009)

Annales de l’institut Fourier

We show that if Γ is a discrete subgroup of the group of the isometries of k , and if ρ is a representation of Γ into the group of the isometries of n , then any ρ -equivariant map F : k n extends to the boundary in a weak sense in the setting of Borel measures. As a consequence of this fact, we obtain an extension of a result of Besson, Courtois and Gallot about the existence of volume non-increasing, equivariant maps. Then, we show that the weak extension we obtain is actually a measurable ρ -equivariant...

Constructing isothermal curvature line coordinates on surfaces which admit them

Eugenio Aulisa, Magdalena Toda, Zeynep Kose (2013)

Open Mathematics

Isothermic parameterizations are synonyms of isothermal curvature line parameterizations, for surfaces immersed in Euclidean spaces. We provide a method of constructing isothermic coordinate charts on surfaces which admit them, starting from an arbitrary chart. One of the primary applications of this work consists of numerical algorithms for surface visualization.

Construction de métriques d’Einstein à partir de transformations biconformes

Laurent Danielo (2006)

Annales de la faculté des sciences de Toulouse Mathématiques

L’objectif de cet article est de proposer une nouvelle méthode de construction de métriques d’Einstein. Le procédé consiste à considérer un morphisme harmonique ϕ : ( M , g ) ( N , h )  ; on déforme ensuite biconformément la métrique g en g ˜ , en conservant l’harmonicité, ce qui simplifie le calcul de la courbure de Ricci. L’équation Ric ˜ = C g ˜ se traduit alors en un système différentiel en termes des paramètres de la déformation. On montre d’abord l’existence de solutions par un procédé dynamique. Puis, on résout ce système dans...

Construction of BGG sequences for AHS structures

Lukáš Krump (2001)

Commentationes Mathematicae Universitatis Carolinae

This paper gives a description of a method of direct construction of the BGG sequences of invariant operators on manifolds with AHS structures on the base of representation theoretical data of the Lie algebra defining the AHS structure. Several examples of the method are shown.

Construction of compact constant mean curvature hypersurfaces with topology

Mohamed Jleli (2012)

Annales de l’institut Fourier

In this paper, we explain how the end-to-end construction together with the moduli space theory can be used to produce compact constant mean curvature hypersurfaces with nontrivial topology. For the sake of simplicity, the hypersurfaces we construct have a large group of symmetry but the method can certainly be used to provide many more examples with less symmetries.

Construction of Einstein metrics by generalized Dehn filling

Richard H. Bamler (2012)

Journal of the European Mathematical Society

In this paper, we present a new approach to the construction of Einstein metrics by a generalization of Thurston's Dehn filling. In particular in dimension 3, we will obtain an analytic proof of Thurston's result.

Construction of Sobolev spaces of fractional order with sub-riemannian vector fields

Sami Mustapha, François Vigneron (2007)

Annales de l’institut Fourier

Given a smooth family of vector fields satisfying Chow-Hörmander’s condition of step 2 and a regularity assumption, we prove that the Sobolev spaces of fractional order constructed by the standard functional analysis can actually be “computed” with a simple formula involving the sub-riemannian distance.Our approach relies on a microlocal analysis of translation operators in an anisotropic context. It also involves classical estimates of the heat-kernel associated to the sub-elliptic Laplacian.

Contact 3-manifolds twenty years since J. Martinet's work

Yakov Eliashberg (1992)

Annales de l'institut Fourier

The paper gives an account of the recent development in 3-dimensional contact geometry. The central result of the paper states that there exists a unique tight contact structure on S 3 . Together with the earlier classification of overtwisted contact structures on 3-manifolds this result completes the classification of contact structures on S 3 .

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