{ "id": "math/0305089", "version": "v1", "published": "2003-05-06T08:50:51.000Z", "updated": "2003-05-06T08:50:51.000Z", "title": "Non-linear Grassmannians as coadjoint orbits", "authors": [ "Stefan Haller", "Cornelia Vizman" ], "journal": "Math. Ann. 329(2004), 771--785.", "categories": [ "math.DG", "math.SG" ], "abstract": "For a given manifold $M$ we consider the non-linear Grassmann manifold $Gr_n(M)$ of $n$-dimensional submanifolds in $M$. A closed $(n+2)$-form on $M$ gives rise to a closed 2-form on $Gr_n(M)$. If the original form was integral, the 2-form will be the curvature of a principal $S^1$-bundle over $Gr_n(M)$. Using this $S^1$-bundle one obtains central extensions for certain groups of diffeomorphisms of $M$. We can realize $Gr_{m-2}(M)$ as coadjoint orbits of the extended group of exact volume preserving diffeomorphisms and the symplectic Grassmannians $SGr_{2k}(M)$ as coadjoint orbits in the group of Hamiltonian diffeomorphisms. We also generalize the vortex filament equation as a Hamiltonian equation on $Gr_{m-2}(M)$.", "revisions": [ { "version": "v1", "updated": "2003-05-06T08:50:51.000Z" } ], "analyses": { "subjects": [ "58B20" ], "keywords": [ "coadjoint orbits", "non-linear grassmannians", "vortex filament equation", "exact volume preserving diffeomorphisms", "non-linear grassmann manifold" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2003math......5089H" } } }