A canonical connection associated with certain -structures
A construction of non-flat non-homogeneous symmetric parabolic geometries
We construct series of examples of non-flat non-homogeneous parabolic geometries that carry a symmetry of the parabolic geometry at each point.
Algèbres de Lie et groupes microlinéaires
Almost invariant submanifolds for compact group actions
We define a distance between submanifolds of a riemannian manifold and show that, if a compact submanifold is not moved too much under the isometric action of a compact group , there is a -invariant submanifold -close to . The proof involves a procedure of averaging nearby submanifolds of riemannian manifolds in a symmetric way. The procedure combines averaging techniques of Cartan, Grove/Karcher, and de la Harpe/Karoubi with Whitney’s idea of realizing submanifolds as zeros of sections...
An algebraic characterization of affine manifolds with -structure satisfying a homogeneity condition.
Canonical form on a groupoid related to regular prolongations of Lie groups
Characterization of Riemannian Manifolds with Weak Homology Group G2 (Following A. Gray).
Classification of invariant AHS-structures on semisimple locally symmetric spaces
We discuss which semisimple locally symmetric spaces admit an AHS-structure invariant under local symmetries. We classify them for all types of AHS-structures and determine possible equivalence classes of such AHS-structures.
Classification of principal connections naturally induced on
We consider a vector bundle and the principal bundle of frames of . Let be a principal connection on and let be a linear connection on . We classify all principal connections on naturally given by and .
Cohomogeneity and positive curvature in low dimensions.
Conditions for integrability of a 3-form
We find necessary and sufficient conditions for the integrability of one type of multisymplectic 3-forms on a 6-dimensional manifold.
Congruences of surfaces in
Connections partially adapted to a metric -structure
Conservation laws and string-like matter distributions
Constant mean curvature palnes with inner rotational symmetry in Euclidean 3-space.
Deformation and equivalence -structures. Part I. -structures
Differential geometry of quaternionic manifolds
Differential operators and -structures of higher order
Duality Properties of Characteristic Forms.
Enveloppe galoisienne d'une application rationnelle de P1.
In 2001, B. Malgrange defines the D-envelope or galoisian envelope of an analytical dynamical system. Roughly speaking, this is the algebraic hull of the dynamical system. In this short article, the D-envelope of a rational map R: P1 --> P1 is computed. The rational maps characterised by a finitness property of their D-envelope appear to be the integrable ones.