BEGIN:VCALENDAR VERSION:2.0 PRODID:-//wp-events-plugin.com//7.2.3.1//EN TZID:Europe/Paris X-WR-TIMEZONE:Europe/Paris BEGIN:VEVENT UID:6367@i2m.univ-amu.fr DTSTART;TZID=Europe/Paris:20210622T110000 DTEND;TZID=Europe/Paris:20210622T120000 DTSTAMP:20241120T201413Z URL:https://www.i2m.univ-amu.fr/evenements/seminaire-de-geometrie-complexe -mardi-22-juin-a-11-h-expose-de-joel-fine-bruxelles-sur-zoom/ SUMMARY: (...): Séminaire de Géométrie Complexe Mardi 22 juin à 11 h ex posé de Joel Fine (Bruxelles) sur ZOOM DESCRIPTION:: Joel Fine (Bruxelles)\n\n \;\n\nTitle: Knots\, minimal su rfaces and J-holomorphic curves.\n\nAbstract: I will describe work in prog ress\, parts of which are joint with Marcelo Alves. Let L be a knot or lin k in the 3-sphere. I will explain how one can count minimal surfaces in hy perbolic 4-space which have ideal boundary equal to L\, and in this way ob tain a knot invariant. In other words the number of minimal surfaces doesn ’t depend on the isotopy class of the link. These counts of minimal surf aces can be organised into a two-variable polynomial which is perhaps a kn own polynomial invariant of the link\, such as HOMFLYPT.\n\n“Counting mi nimal surfaces” needs to be interpreted carefully here\, similar to how Gromov-Witten invariants “count” J-holomorphic curves. Indeed I will e xplain how this “minimal surface polynomial" can be seen as a Gromov-Wit ten invariant for the twistor space of hyperbolic 4-space. This leads natu rally to a new class of infinite-volume 6-dimensional symplectic manifolds with well behaved counts of J-holomorphic curves. This gives more potenti al knot invariants\, for knots in 3-manifolds other than the 3-sphere. It also enables the counting of minimal surfaces in more general Riemannian 4 -manifolds\, besides hyperbolic space. CATEGORIES:Séminaire END:VEVENT BEGIN:VTIMEZONE TZID:Europe/Paris X-LIC-LOCATION:Europe/Paris BEGIN:DAYLIGHT DTSTART:20210328T030000 TZOFFSETFROM:+0100 TZOFFSETTO:+0200 TZNAME:CEST END:DAYLIGHT END:VTIMEZONE END:VCALENDAR