A characterization of certain branched coverings as group actions
A flat manifold with no symmetries.
A lower bound to the action dimension of a group.
Actions of Groups with Periodic Cohomology on Poincaré Duality Spaces.
Almost-Bieberbach groups with prime order holonomy
The main issue of this paper is an attempt to find a decomposition theorem for infra-nilmanifolds in the same spirit as a result of A. Vasquez for flat Riemannian manifolds. That is: we look for infra-nilmanifolds with prime order holonomy which can be obtained as a fiber space with a non-trivial nilmanifold as fiber and an infra-nilmanifold as its base. In this perspective, we prove the following algebraic result: if E is an almost-Bieberbach group with prime order holonomy,...
Amenable hyperbolic groups
We give a complete characterization of the locally compact groups that are non elementary Gromov-hyperbolic and amenable. They coincide with the class of mapping tori of discrete or continuous one-parameter groups of compacting automorphisms. We moreover give a description of all Gromov-hyperbolic locally compact groups with a cocompact amenable subgroup: modulo a compact normal subgroup, these turn out to be either rank one simple Lie groups, or automorphism groups of semiregular trees acting doubly...
Anosov theorem for coincidences on nilmanifolds
Suppose that L, L’ are simply connected nilpotent Lie groups such that the groups and in their lower central series have the same dimension. We show that the Nielsen and Lefschetz coincidence numbers of maps f,g: Γ∖L → Γ’∖L’ between nilmanifolds Γ∖L and Γ’∖L’ can be computed algebraically as follows: L(f,g) = det(G⁎ - F⁎), N(f,g) = |L(f,g)|, where F⁎, G⁎ are the matrices, with respect to any preferred bases on the uniform lattices Γ and Γ’, of the homomorphisms between the Lie algebras , ’ of...
Bootstrapping in convergence groups.
Cellular Actions and Groups of Finite Quasi-Projective Dimension.
Cohomology of Fixed Point Sets and Deformation of Algebras.
Collars in PSL.
Compact flat manifolds with holonomy group (II)
Compact solvmanifolds of dimension at most 4.
Complex analytic geometry of complex parallelizable manifolds
Crooked planes.
Discontinuous groups in some metric and nonmetric spaces
Enden von Räumen mit eigentlichen Transformationsgruppen
Equivariant embeddings of finite abelian group actions in euclidean space
Equivariant Euler characteristics and -homology Euler classes for proper cocompact -manifolds.
Equivariant rigidity theorems.