On semi-global invariants for focus-focus singularities
Abstract
Description
This article gives a classification, up to symplectic equivalence, of singular Lagrangian foliations given by a completely integrable system of a 4-dimensional symplectic manifold, in a full neighbourhood of a singular leaf of focus-focus (=nodal) type.
19 pages 4 fig. Written in june 2001. To appear in Topology
19 pages 4 fig. Written in june 2001. To appear in Topology