On a class of non linear differential operators of first order with singular point.
On classical intrinsically resonant formal perturbation theory
On quadratic symplectic mappings.
On the Birkhoff normal form of a completely integrable hamiltonian system near a fixed point with resonance
On vanishing inflection points of plane curves
We study the local behaviour of inflection points of families of plane curves in the projective plane. We develop normal forms and versal deformation concepts for holomorphic function germs which take into account the inflection points of the fibres of . We give a classification of such function- germs which is a projective analog of Arnold’s A,D,E classification. We compute the versal deformation with respect to inflections of Morse function-germs.