Derivations on the restricted Nijenhuis-Schouten bracket algebra
Description canonique de champs de vecteurs sur une surface
On étudie dans cet article les champs de vecteurs de classe sur les surfaces compactes éventuellement à bord. On montre que si les singularités sont des selles sans liaison entre elles, s’il n’y a pas de feuille compacte intérieure et si le champ est transverse au bord, la surface admet une décomposition canonique. Suivant les cas cette décomposition comporte au plus trois ou quatre composantes. L’une est orientable sans bord, l’une est non orientable sans bord et il reste soit une composante...
Differential equations in metric spaces
Differential equations in metric spaces
We give a meaning to derivative of a function , where is a complete metric space. This enables us to investigate differential equations in a metric space. One can prove in particular Gronwall’s Lemma, Peano and Picard Existence Theorems, Lyapunov Theorem or Nagumo Theorem in metric spaces. The main idea is to define the tangent space of . Let , be continuous at zero. Then by the definition and are in the same equivalence class if they are tangent at zero, that is if By we denote...
Dimension des orbites d'une action de ... sur une variété compacte.
Equivariant Frame Fields on Spheres with complementary equivariant complex structures.
Extension of cross-sections and a generalized de Rham theorem.
Fields of 2-planes and two kinds of almost complex structures on compact 4-dimensional manifolds.
Fields of 2-Planes on Compact Simply-Connected Smooth 4-Manifolds.
Finitely Determined Singularities of Formal Vector Fields.
Fixed point free equivariant homotopy classes
Fixed point indices and manifolds with collars.
Foliations by planes and Lie group actions
Let N be a closed orientable n-manifold, n ≥ 3, and K a compact non-empty subset. We prove that the existence of a transversally orientable codimension one foliation on N∖K with leaves homeomorphic to , in the relative topology, implies that K must be connected. If in addition one imposes some restrictions on the homology of K, then N must be a homotopy sphere. Next we consider C² actions of a Lie group diffeomorphic to on N and obtain our main result: if K, the set of singular points of the...
Fundamental vector fields on associated fiber bundles
Fundamental vector fields on type fibres of jet prolongations of tensor bundles
Generic properties of parametrized vectorfields. I
Gradient homotopies of gradient vector fields
Growth of Jacobi Fields and Divergence of Geodesics.
Harmonic Analysis for Vector Fields on Hyperbolic Spaces.
Holomorphic Vector Fields with Simple Isolated Zeros.