BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Marc Mars (University of Salamanca) DTSTART:20250508T134000Z DTEND:20250508T143000Z DTSTAMP:20260423T023047Z UID:jomarec/42 DESCRIPTION:Title: Null geometry and applications to existence of spacetimes\nby Marc Ma rs (University of Salamanca) as part of JoMaReC - Joint Online Mathematica l Relativity Colloquium\n\n\nAbstract\nNon-null hypersurfaces can be easil y viewed as geometric objects detached from the spacetime where they are e mbedded. This process of "detachment" is more complicated in the case of n ull hypersurfaces. In this talk I will introduce the notion of "null manif old"\, together with related concepts such as "ruled null manifold" or "me tric hypersurface data"\, as a way to study null hypersurfaces from a full y detached point of view. With this framework at hand\, I will then discus s three applications related to existence of spacetimes. Specifically\, I will present a detached version of the characteristic initial value proble m\, a general analysis of transverse expansions across a null hypersurface and an existence and asymptotic uniqueness result of $\\Lambda$-vacuum sp acetimes from data on a (detached) non-degenerate Killing horizon. The thr ee applications are joint work with Gabriel Sánchez Pérez.\n\nwill be st reamed from the GAPs conference at IMAG https://www.birs.ca/events/2025/5- day-workshops/25w5397\n LOCATION:https://researchseminars.org/talk/jomarec/42/ END:VEVENT END:VCALENDAR