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DTSTART;VALUE=DATE:20100309T171500
DTEND;VALUE=DATE:20100309T171500
UID:5606@agenda.unifr.ch
DESCRIPTION:If a Riemannian 2-dimensional manifold M is not simply connected,\nproducing a nontrivial closed geodesic is relatively simple: it suffices\nto minimize the length among all noncontractible loops. Obviously,\nthis method does not apply when M is diffeomorphic to the sphere.\nNonetheless, in a pioneering work which appeared in 1917, Birkhoff\nshowed the existence of at least a nontrivial closed geodesic even in\nthe latter case. A subsequence celebrated refinement of Ljusternik and\nShnirelman showed indeed that there are always at least three distinct\nclosed geodesics.\n<br />\n The proof of Birkhoff is probably the first ""min-max"" argument in\nthe calculus of variations. In this talk we will address higher dimensional versions of his method, showing how to produce minimal hyper-surfaces, i.e. critical points of the area functional, in a quite general setting.\n<br />\n[Invited by Prof. Ruth Kellerhals]\n
SUMMARY:Prof. Dr. Camillo DE LELLIS (Universität Zürich): Minmax constructions of minimal surfaces
CATEGORIES:Colloque / Congrès / Forum
LOCATION:PER 08\, Phys 2.52\, Chemin du Musée 3\, 1700 Fribourg
URL;VALUE=URI:https://agenda.unifr.ch/e/fr/5606
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