EQUIVALENCE OF LAGRANGIAN GERMS IN THE PRESENCE OF A SURFACE

Dedicated to Professor Stanis law Lojasiewicz for his 70th birthday 1. Introduction. Let ω be a closed two-form on a smooth manifoldM. Most of inter-esting singular symplectic structures on M are given in the form of pull-back ω = φ?ω0 by a smooth map φ: M → R2n from a symplectic structure ω0 on R2n [7, 9, 5, 6]. The natural structure group of such singular symplectic manifolds is defined by integration of φ−liftable Hamiltonian vector fields on (R2n, ω0). Action of this group on the space o