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Hofer’s metrics and boundary depth

Michael Usher (2013)

Annales scientifiques de l'École Normale Supérieure

We show that if ( M , ω ) is a closed symplectic manifold which admits a nontrivial Hamiltonian vector field all of whose contractible closed orbits are constant, then Hofer’s metric on the group of Hamiltonian diffeomorphisms of  ( M , ω ) has infinite diameter, and indeed admits infinite-dimensional quasi-isometrically embedded normed vector spaces. A similar conclusion applies to Hofer’s metric on various spaces of Lagrangian submanifolds, including those Hamiltonian-isotopic to the diagonal in  M × M when M satisfies...

Invariants analytiques des champs de vecteurs de n , 0

Jean-Pierre Francoise (1985)

Annales de l'institut Fourier

On démontre qu’il ne peut exister de système complet d’invariants analytiques pour l’action du groupe des germes des difféomorphismes sur les champs de vecteurs pour un champ dont la forme normale a un champ réduit associé nul.

Ito equation as a geodesic flow on Diff s ( S 1 ) C ( S 1 ) ^

Partha Guha (2000)

Archivum Mathematicum

The Ito equation is shown to be a geodesic flow of L 2 metric on the semidirect product space 𝐷𝑖𝑓𝑓 s ( S 1 ) C ( S 1 ) ^ , where 𝐷𝑖𝑓𝑓 s ( S 1 ) is the group of orientation preserving Sobolev H s diffeomorphisms of the circle. We also study a geodesic flow of a H 1 metric.

Lie group structures on groups of diffeomorphisms and applications to CR manifolds

M. Salah Baouendi, Linda Preiss Rothschild, Jörg Winkelmann, Dimitri Zaitsev (2004)

Annales de l’institut Fourier

We give general sufficient conditions to guarantee that a given subgroup of the group of diffeomorphisms of a smooth or real-analytic manifold has a compatible Lie group structure. These results, together with recent work concerning jet parametrization and complete systems for CR automorphisms, are then applied to determine when the global CR automorphism group of a CR manifold is a Lie group in an appropriate topology.

Local density of diffeomorphisms with large centralizers

Christian Bonatti, Sylvain Crovisier, Gioia M. Vago, Amie Wilkinson (2008)

Annales scientifiques de l'École Normale Supérieure

Given any compact manifold M , we construct a non-empty open subset 𝒪 of the space Diff 1 ( M ) of C 1 -diffeomorphisms and a dense subset 𝒟 𝒪 such that the centralizer of every diffeomorphism in 𝒟 is uncountable, hence non-trivial.

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