Dicovering spaces.
Dualité dans les revetements galoisiens.
Embedding Finite Covering Spaces into Trivial Bundles.
End reductions, fundamental groups, and covering spaces of irreducible open 3-manifolds.
Equivariant covering spaces and homotopy covering spaces.
Fast genügend große irreduzible 3-dimensionale Mannigfaltigkeiten.
Fatness of covers.
Flensted-Jensen's functions attached to the Landau problem on the hyperbolic disc
We give an explicit expression of a two-parameter family of Flensted-Jensen’s functions on a concrete realization of the universal covering group of . We prove that these functions are, up to a phase factor, radial eigenfunctions of the Landau Hamiltonian on the hyperbolic disc with a magnetic field strength proportional to , and corresponding to the eigenvalue .
Formes hermitiennes sur les -modules
Fundamental pro-groupoids and covering projections
We introduce a new notion of covering projection E → X of a topological space X which reduces to the usual notion if X is locally connected. We use locally constant presheaves and covering reduced sieves to find a pro-groupoid π crs (X) and an induced category pro (π crs (X), Sets) such that for any topological space X the category of covering projections and transformations of X is equivalent to the category pro (π crs (X), Sets). We also prove that the latter category is equivalent to pro (π CX,...
Generalized orbifold Euler characteristics of symmetric orbifolds and covering spaces.
Generalized universal covering spaces and the shape group
If a paracompact Hausdorff space X admits a (classical) universal covering space, then the natural homomorphism φ: π₁(X) → π̌₁(X) from the fundamental group to its first shape homotopy group is an isomorphism. We present a partial converse to this result: a path-connected topological space X admits a generalized universal covering space if φ: π₁(X) → π̌₁(X) is injective. This generalized notion of universal covering p: X̃ → X enjoys most of the usual properties, with the possible exception of evenly...
Gradients de Heegaard sous-logarithmiques d’une variété hyperbolique de dimension trois et fibres virtuelles
J. Maher a montré qu’une variété hyperbolique de dimension compacte sans bord, connexe et orientable fibre virtuellement sur le cercle si et seulement si elle admet une famille infinie de revêtements finis de genre de Heegaard borné. En s’appuyant sur la démonstration de Maher, cet article présente un théorème donnant une condition suffisante pour qu’un revêtement fini d’une variété hyperbolique compacte de dimension contienne une fibre virtuelle, qui s’exprime en fonction du degré du revêtement...
Group structure in finite coverings of compact solenoidal groups.
Groups acting on covering spaces
Group-theoretic conditions under which closed aspherical manifolds are covered by Euclidean space
Hass, Rubinstein, and Scott showed that every closed aspherical (irreducible) 3-manifold whose fundamental group contains the fundamental group of a closed aspherical surface, is covered by Euclidean space. This theorem does not generalize to higher dimensions. However, we provide geometric tools with which variations of this theorem can be proved in all dimensions.
Heegaard gradient and virtual fibers.
Heegaard splittings and virtually Haken Dehn filling.
Heegaard splittings and virtually Haken Dehn filling. II.
Holomorphic Projective Structures on Compact Complex Surfaces. II.