Concept

Hyperbolic space

Related publications (35)

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Numerical simulations with a first-order BSSN formulation of Einstein's field equations

Jan Sickmann Hesthaven

We present a new fully first-order strongly hyperbolic representation of the Baumgarte-Shapiro-Shibata-Nakamura formulation of Einstein's equations with optional constraint damping terms. We describe the characteristic fields of the system, discuss its hyp ...

AMER PHYSICAL SOC2012

Weakly regular subdivisions

Lionel Pournin

It is shown that 2-dimensional subdivisions can be made regular by moving their vertices within parallel 1-dimensional spaces. As a consequence, any 2-dimensional subdivision is projected from the boundary complex of a 4-polytope. ...

Springer-Verlag2012

Isometry groups of non-positively curved spaces: Discrete subgroups

Nicolas Monod

We study lattices in non-positively curved metric spaces. Borel density is established in that setting as well as a form of Mostow rigidity. A converse to the flat torus theorem is provided. Geometric arithmeticity results are obtained after a detour throu ...

2009

Fixed point free involutions on Riemann surfaces

Hugo Parlier

In this paper, involutions without fixed points on hyperbolic closed Riemann surface are discussed. For an orientable surface X of even genus with an arbitrary Riemannian metric d admitting an involution tau, it is known that min (p is an element of X) d(p ...

The Hebrew University Magnes Press, Springer2008

Exploring light propagating in photonic crystals with Fourier optics

Romuald Houdré, Nicolas Le Thomas

Photonic crystals (PhCs) act on light in two different ways: confinement and modification of propagation. Both phenomena rely on the complex interplay between multiply scattered waves that can form what is known as a Bloch mode. Here, we present a techniqu ...

Optical Society of America2007

Continuous Wavelet Transform on the Hyperboloid

Pierre Vandergheynst, Iva Bogdanova Vandergheynst

In this paper we build a Continuous Wavelet Transform (CWT) on the upper sheet of the 2-hyperboloid

H_+^2

. First, we define a class of suitable dilations on the hyperboloid through conic projection. Then, incorporating hyperbolic motions belonging to $SO ...

2007

Stability of spherically symmetric wave maps

Joachim Krieger

We study Wave Maps from R2+1 to the hyperbolic plane H-2 with smooth compactly supported initial data which are close to smooth spherically symmetric initial data with respect to some H1+mu, mu > 0. We show that such Wave Maps don't develop singularities i ...

2006

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

Trace coordinates of Teichmüller space of Riemann surfaces of signature $(0,4)$

Klaus-Dieter Semmler, Thomas Gauglhofer

Summary: We explicitly give

calT

, the Teichmüller space of four-holed spheres (which we call

X

pieces) in trace coordinates, as well as its modular group and a fundamental domain for the action of this group on

calT

which is its moduli space. As a co ...

2005

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

Continuous Wavelet Transform on the Hyperboloid

Pierre Vandergheynst, Iva Bogdanova Vandergheynst

In this paper we build a Continuous Wavelet Transform (CWT) on the upper sheet of the 2-hyperboloid

H_+^2

. First, we define a class of suitable dilations on the hyperboloid through conic projection. Then, incorporating hyperbolic motions belonging to $SO ...

2007

Trace coordinates of Teichmüller space of Riemann surfaces of signature $(0,4)$

Klaus-Dieter Semmler, Thomas Gauglhofer

Summary: We explicitly give

calT

, the Teichmüller space of four-holed spheres (which we call

X

pieces) in trace coordinates, as well as its modular group and a fundamental domain for the action of this group on

calT

which is its moduli space. As a co ...

2005

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