BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Dima Faifman (Tel Aviv University) DTSTART:20201110T153000Z DTEND:20201110T163000Z DTSTAMP:20260423T021238Z UID:OAGAS/41 DESCRIPTION:Title: C rofton formulas in isotropic pseudo-Riemannian spaces\nby Dima Faifman (Tel Aviv University) as part of Online asymptotic geometric analysis sem inar\n\n\nAbstract\nThe length of a curve in the plane can be computed by counting the intersection points with a line\, and integrating over all li nes. More generally\, the intrinsic volumes (quermassintegrals) of a subse t of Euclidean space can be computed by Crofton integrals\, bringing forth their fundamental role in integral geometry. In spherical and hyperbolic geometry\, such formulas are also known and classical. In pseudo-Riemannia n isotropic spaces\, such as de Sitter or anti-de Sitter space\, one can s imilarly ask for an integral-geometric formula for the volume of a submani fold\, or more generally for the intrinsic volumes of a subset\, which wer e introduced only recently. I will explain how to obtain and apply such fo rmulas\, and how in fact there is a universal Crofton formula depending on a complex parameter extending the Riemannian Crofton formulas\, for which all indefinite signatures are distributional boundary values. This is a j oint work in progress with Andreas Bernig and Gil Solanes.\n LOCATION:https://researchseminars.org/talk/OAGAS/41/ END:VEVENT END:VCALENDAR