Topology & Geometric Group Theory Seminar

Fall 2011

1:30 – 2:30, Malott 203

Tuesday, September 20

Reyer Sjamaar, Cornell University

(Almost) Lagrangian fibre bundles

(Almost) Lagrangian fibre bundles arise from completely integrable Hamiltonian systems. Such bundles have local normal forms ("action-angle variables") and have no local invariants. Two global invariants, the monodromy and the Chern class, were identified by Duistermaat. A refinement of the Chern class, now called the Lagrangian class, was found by Dazord and Delzant. In this survey talk I will define these invariants and show how they classify (almost) Lagrangian fibre bundles.

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