Recognition of -singularities of functions.
Reducibility theorems for differentiable liftings in fiber bundles
Relative cohomology and volume forms
Remarks on the symmetries of planar fronts.
A front is the projection on the plane of a Legendrian immersion of a circle in the space of the contact elements of that plane. I analyze the symmetries of a generic front with respect to the group generated by the involutions reversing the orientation of the plane, the orientation of the preimage circle and the coorientation of the contact plane.
Removable singularities for the Yang-Mills-Higgs equations in two dimensions
Résultats nouveaux a propos des conjectures de Lichnerowicz et de Carathéodory