-bundles and exotic actions
Schwarzian derivative related to modules of differential operators on a locally projective manifold
We introduce a 1-cocycle on the group of diffeomorphisms Diff(M) of a smooth manifold M endowed with a projective connection. This cocycle represents a nontrivial cohomology class of Diff(M) related to the Diff(M)-modules of second order linear differential operators on M. In the one-dimensional case, this cocycle coincides with the Schwarzian derivative, while, in the multi-dimensional case, it represents its natural and new generalization. This work is a continuation of [3] where the same problems...
Self-homeomorphisms of the 2-sphere which fix pointwise a nonseparating continuum
We prove that the space of orientation preserving homeomorphisms of the 2-sphere which fix pointwise a nontrivial nonseparating continuum is a contractible absolute neighborhood retract homeomorphic to the separable Hilbert space .
Semi-Free Circel Actions on Spheres.
Semifree Topological Actions of Finite Groups on Spheres.
Semi-free Zp-Actions on Highly-Connected Manifolds.
Smith equivalence and finite Oliver groups with Laitinen number 0 or 1.
Smooth Compact Lie Group Actions on Disks.
Some examples of spherical orbit spaces with cohomogeneity 2.
Some Non-Linear Equivariant Sphere Bundles
Some PL involutions of product 3-manifolds which preserve the center of the fundamental group
Some results and conjectures on finite groups acting on homology spheres.
Sommes connexes fibrées en cercles
Spherical isotropy representations
Spin c-Structures and S1-Actions.
Structural Theorems for Topological Actions of Z...-Tori on Real, Complex and Quarternionic Projective Spaces
Structures différentiables sur les types d'homotopie rationnelle simplement connexes
Submanifolds of codimension two and homology equivalent manifolds
In this paper new methods of studying codimension two embeddings of manifolds are outlined. Results are stated on geometric periodicity of knot cobordism. The group of local knots of a manifold in a 2-plane bundle is introduced and computed, and applied to -close embeddings. General codimension two splitting theorems are discussed, with applications to equivariant knots and knot cobordism. A general existence theorem for P.L. (non-locally flat) embeddings is also given.The methods involve some...
Sur les feuilletages induits par l'action de groupes de Lie nilpotents
Nous étudions ici les feuilletages de codimension un induits par les actions non dégénérées de groupes nilpotents.L’existence de feuilles non compactes isolées d’un côté, implique celle d’idéaux remarquables dans l’algèbre de Lie du groupe.Dans la deuxième partie, nous montrons, dans le cas des groupes de Heisenberg des théorèmes de fibration et de cobordisme généralisant ceux obtenus par H. Rosenberg et l’auteur pour (cf. Cahiers IHES, 1974).
Sur les opérations holomorphes du groupe additif complexe sur l'espace de deux variables complexes