A convex Darboux theorem
A generalization of the exterior product of differential forms combining Hom-valued forms
This article deals with vector valued differential forms on -manifolds. As a generalization of the exterior product, we introduce an operator that combines -valued forms with -valued forms. We discuss the main properties of this operator such as (multi)linearity, associativity and its behavior under pullbacks, push-outs, exterior differentiation of forms, etc. Finally we present applications for Lie groups and fiber bundles.
A map associated to the Lepagian forms on the calculus of variations in fibred manifolds
A remark on linear functions on the sphere
Abstract exterior differential
Affine differential invariants for planar curves.
An inverse problem in the economic theory of demand
Automorphism Groups of Classical Mechanical Systems.
Boundaries of graphs of harmonic functions.
Canonical form on a groupoid related to regular prolongations of Lie groups
Contact geometry of curves.
Corrections to the paper: “On formal theory of differential equations. II.”
Curvature and the equivalence problem in sub-Riemannian geometry
These notes give an introduction to the equivalence problem of sub-Riemannian manifolds. We first introduce preliminaries in terms of connections, frame bundles and sub-Riemannian geometry. Then we arrive to the main aim of these notes, which is to give the description of the canonical grading and connection existing on sub-Riemann manifolds with constant symbol. These structures are exactly what is needed in order to determine if two manifolds are isometric. We give three concrete examples, which...
E. E. Levi convexity and the Hans Lewy problem. Part I : reduction to vanishing theorems
Equivalence problem for minimal rational curves with isotrivial varieties of minimal rational tangents
We formulate the equivalence problem, in the sense of É. Cartan, for families of minimal rational curves on uniruled projective manifolds. An important invariant of this equivalence problem is the variety of minimal rational tangents. We study the case when varieties of minimal rational tangents at general points form an isotrivial family. The main question in this case is for which projective variety , a family of minimal rational curves with -isotrivial varieties of minimal rational tangents...
Espaces variationnels et mécanique
Ce travail est essentiellement consacré aux systèmes dynamiques non conservatifs, la force généralisée dépendant à la fois des paramètres de position et de vitesse . désignant l’espace-temps de configuration, l’espace fibré des vecteurs tangents, celui des directions tangentes à , on caractérise par son lagrangien homogène et le tenseur-force antisymétrique dont le produit contracté par le vecteur vitesse donne le vecteur force généralisé.Dans la première partie, on étudie l’algèbre...
Explicit expression of Cartan’s connection for Levi-nondegenerate 3-manifolds in complex surfaces, and identification of the Heisenberg sphere
We study effectively the Cartan geometry of Levi-nondegenerate C 6-smooth hypersurfaces M 3 in ℂ2. Notably, we present the so-called curvature function of a related Tanaka-type normal connection explicitly in terms of a graphing function for M, which is the initial, single available datum. Vanishing of this curvature function then characterizes explicitly the local biholomorphic equivalence of such M 3 ⊂ ℂ2 to the Heisenberg sphere ℍ3, such M’s being necessarily real analytic.
Exterior differential systems for Yang-Mills theories.
Fibre integration and some of its applications.
Galilean geometry of motions.