Catégorie

Géométrie non euclidienne

Publications associées (28)

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Applications of a theorem of Singerman about Fuchsian groups

Hugo Parlier

Assume that we have a (compact) Riemann surface S, of genus greater than 2, with S = D/Gamma, where D is the complex unit disc and Gamma is a surface Fuchsian group. Let us further consider that S has an automorphism group G in such a way that the orbifold ...

2008

Laplacian Operator, Diffusion Flow and Active Contour on non-Euclidean Images

Jean-Philippe Thiran, Pierre Vandergheynst, Xavier Bresson, Iva Bogdanova Vandergheynst

We propose here some basic approaches to direct processing of the

360^o

-images as we take into consideration the geometry of each one. Obviously, the geometry of each of these images is a consequence of the geometry of the sensor's mirror used. This tech ...

2005

Equivariant embeddings of trees into hyperbolic spaces

Nicolas Monod

We study isometric actions of tree automorphism groups on the infinite-dimensional hyperbolic spaces. On the one hand, we exhibit a general one-parameter family of such representations and analyse the corresponding equivariant embeddings of the trees, show ...

2005

Ideal bicombings for hyperbolic groups and applications

Nicolas Monod

For every hyperbolic group and more general hyperbolic graphs, we construct an equivariant ideal bicombing: this is a homological analogue of the geodesic flow on negatively curved manifolds. We then construct a cohomological invariant which implies that s ...

2004

Standard continuous Galerkin-based finite element methods have poor stability properties when applied to transport-dominated flow problems, so excessive numerical stabilization is needed. In contrast, the Discontinuous Galerkin method is known to have good ...

2004

Classical print reflection models: a radiometric approach

Roger Hersch, Mathieu Hébert

The present contribution reviews the classical print prediction models of Williams and Clapper and of Clapper and Yule by pursuing a radiometric approach. The relationship between these models is established and the related respective contributions of Judd ...

Soc. Imaging Sci. & Technol2004

Axiomatic theory of Sobolev spaces

Marc Troyanov

We develop an axiomatic approach to the theory of Sobolev spaces on metric measure spaces and we show that this axiomatic construction covers the main known examples (Hajlasz Sobolev spaces, weighted Sobolev spaces, Upper-radients, etc). We then introduce ...

2001

A framework for the construction of stable spectral methods on arbitrary domains with unstructured grids is presented. Although most of the developments are of a general nature, an emphasis is placed on schemes for the solution of partial differential equa ...

SIAM PUBLICATIONS2000

Laplacian Operator, Diffusion Flow and Active Contour on non-Euclidean Images

Jean-Philippe Thiran, Pierre Vandergheynst, Xavier Bresson, Iva Bogdanova Vandergheynst

We propose here some basic approaches to direct processing of the

360^o

-images as we take into consideration the geometry of each one. Obviously, the geometry of each of these images is a consequence of the geometry of the sensor's mirror used. This tech ...

2005