Search results for "hyperbolic geometry"

Sur la r�gularit� de la fonction croissance d'une vari�t� riemannienne

1994

On etudie la differentiabilite de la fonction croissance d'une variete riemannienne complete. En general, elle a la meme regularite qu'une fonction concave: la derivee peut avoir des sauts pour lesquels on donne une formule. Dans le cas analytique reel, la fonction croissance est de classeC1. Un exemple montre qu'elle n'est pas necessairementC2. A titre d'application, nous construisons, pour toute variete ouverte paracompacteM et toute fonction croissantev de classeC1, une metrique continue de croissance egale av et une metrique de classeC∞ surM de croissance proche dev en topologieC1-fine.

�ber niedrigdimensionale projektive Darstellungen von Kettengeometrien

1985

Parallelismen in unendlichen projektiven R�umen endlicher Dimension

1978

Projektiv darstellbare stark planare Geometrien vom Rang 4

1976

Kleinste Kleinsche Flaschen mit Rand

1979

Charakterisierung (A, B)-regul�rer faserungen durch schliessungss�tze

1977

On stable geometries

1994

Within the concept of projective lattice geometry we are considering the class of stable geometries which have also been introduced in [14]. The investigation of their basic properties will result in fundamental structure theorems which especially give a lattice-geometric characterization of free left modules of rank ≥6 over proper right Bezout rings of stable rank 2. This yields a proper generalization of previous results of ours.

On the topology of surfaces with the generalised simple lift property.

2020

In this paper, we study the geometry of surfaces with the generalised simple lift property. This work generalises previous results by Bernstein and Tinaglia, and it is motivated by the fact that leaves of a minimal lamination obtained as a limit of a sequence of properly embedded minimal disks satisfy the generalised simple lift property.

On Barbilian spaces in projective lattice geometries

1992

We introduce the notion of a Barbilian space of a projective lattice geometry in order to investigate the relationship between lattice-geometric properties and the properties of point-hyperplane structures associated with. We obtain a characterization of those projective lattice geometries, the Barbilian space of which is a Veldkamp space.

On the representation of integers by indefinite binary Hermitian forms

2011

Given an integral indefinite binary Hermitian form f over an imaginary quadratic number field, we give a precise asymptotic equivalent to the number of nonequivalent representations, satisfying some congruence properties, of the rational integers with absolute value at most s by f, as s tends to infinity.