Loops in the Hamiltonian group: a survey

dc.creatorMcDuff, Dusa
dc.date2007-11-26
dc.date2009-01-18
dc.date.accessioned2026-07-07T12:30:46Z
dc.date.available2026-07-07T12:30:46Z
dc.descriptionThis note describes some recent results about the homotopy properties of Hamiltonian loops in various manifolds, including toric manifolds and one point blow ups. We describe conditions under which a circle action does not contract in the Hamiltonian group, and construct an example of a loop $\ga$ of diffeomorphisms of a symplectic manifold M with the property that none of the loops smoothly isotopic to $\ga$ preserve any symplectic form on M. We also discuss some new conditions under which the Hamiltonian group has infinite Hofer diameter. Some of the methods used are classical (Weinstein's action homomorphism and volume calculations), while others use quantum methods (the Seidel representation and spectral invariants).
dc.description24 pages, talk given at AMS Summer 2007 Conference, Snowbird, UT; v2 has very minor revisions
dc.identifierhttps://arxiv.org/abs/0711.4086
dc.identifierhttp://arxiv.org/abs/0711.4086
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/216234
dc.subjectSymplectic Geometry
dc.subject53D45,57R17,57S05
dc.titleLoops in the Hamiltonian group: a survey
dc.typetext

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