BEGIN:VCALENDAR VERSION:2.0 PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4// BEGIN:VEVENT UID:20250704T185315EDT-4168c8PuLM@132.216.98.100 DTSTAMP:20250704T225315Z DESCRIPTION:Abstract: The first subject of this talk is an isoperimetric ine quality for the second non-zero eigenvalue of the Laplace-Beltrami operato r on the real projective plane (based on a joint paper with N. Nadirashvil i). For a metric of area 1 this eigenvalue is not greater than 20\pi. This value could be attained as a limit on a sequence of metrics of area 1 on the projective plane converging to a singular metric on the projective pla ne and the sphere with standard metrics touching in a point such that the ratio of the areas of the projective plane and the sphere is 3:2. The seco nd subject of this talk is a very recent result (joint paper with M. Karpu khin\, N. Nadirashvili and I. Polterovich) about an isoperimetric inequali ty for Laplace eigenvalues on the sphere. For a metric of area 1 the k-th eigenvalue is not greater than 8\pi k. This value could be attained as a l imit on a sequence of metrics of area 1 on the sphere converging to a sing ular metric on k spheres with standard metrics of equal radius touching in a point.\n DTSTART:20170828T173000Z DTEND:20170828T183000Z LOCATION:Room 5183\, CA\, University de Montreal SUMMARY:Alexei Penskoi (Moscow State University and Higher School of Econom ics) URL:/mathstat/channels/event/alexei-penskoi-moscow-sta te-university-and-higher-school-economics-269574 END:VEVENT END:VCALENDAR