The Bernoulli manifolds for nonelliptic quasilinear systems of first order and applications in continuum mechanics
The differential form method for finding symmetries.
The geometry of the space of Cauchy data of nonlinear PDEs
First-order jet bundles can be put at the foundations of the modern geometric approach to nonlinear PDEs, since higher-order jet bundles can be seen as constrained iterated jet bundles. The definition of first-order jet bundles can be given in many equivalent ways - for instance, by means of Grassmann bundles. In this paper we generalize it by means of flag bundles, and develop the corresponding theory for higher-oder and infinite-order jet bundles. We show that this is a natural geometric framework...
The group structure of supergravity
The positive radial solutions of a class of semilinear elliptic equations.
The role of symmetry and separation in surface evolution and curve shortening.
The surjectivity of a constant coefficient homogeneous differential operator in the real analytic functions and the geometry of its symbol
Hörmander has characterized the surjective constant coefficient partial differential operators on the space of all real analytic functions on by a Phragmén-Lindelöf condition. Geometric implications of this condition and, for homogeneous operators, of the corresponding condition for Gevrey classes are given.
The two-dimensional eikonal equation.
Transformation de Kelvin et ondes non linéaires globales
Transformations of differential equations
Travelling wave solutions for the KdV-Burgers-Kuramoto and nonlinear Schrödinger equations which describe pseudospherical surfaces.
Triangulation formelle de certains systèmes de Pfaff complètement intégrables et application à l’étude des systèmes non linéaires