Dazord, Pierre; Delzant, Thomas Classe de Chern de certaines fibrations isotropes. (Chern class of some isotrope fibrations). (French) Zbl 0577.55014 C. R. Acad. Sci., Paris, Sér. I 300, 137-140 (1985). According to the Liouville theorem a phase space of an integrable Hamiltonian system carries a structure of toroidal Lagrangian bundle and local action-angle variables. A more general situation of isotropic toroidal foliations on symplectic manifolds is considered and obstructions for the existence of global action-angle variables are constructed. Reviewer: A.Givental’ Cited in 1 Review MSC: 55R40 Homology of classifying spaces and characteristic classes in algebraic topology 55S40 Sectioning fiber spaces and bundles in algebraic topology 37J99 Dynamical aspects of finite-dimensional Hamiltonian and Lagrangian systems Keywords:Poisson manifolds; characteristic classes; integrable Hamiltonian system; toroidal Lagrangian bundle; action-angle variables; isotropic toroidal foliations; symplectic manifolds PDFBibTeX XMLCite \textit{P. Dazord} and \textit{T. Delzant}, C. R. Acad. Sci., Paris, Sér. I 300, 137--140 (1985; Zbl 0577.55014)