BEGIN:VCALENDAR VERSION:2.0 PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4// BEGIN:VEVENT UID:20251019T005501EDT-5098bJRbVe@132.216.98.100 DTSTAMP:20251019T045501Z DESCRIPTION:Title: Concavity of solutions to elliptic equations on the sphe re\n Abstract: An important question in PDE is when a solution to an ellipt ic equation is concave. This has been of interest with respect to the spec trum of linear equations as well as in nonlinear problems. An old techniqu e going back to works of Korevaar\, Kennington and Kawohl is to study a ce rtain two-point function on a Euclidean domain to prove a so-called concav ity maximum principle with the help of a first and second derivative test. \n To our knowledge\, so far this technique has never been transferred to o ther ambient spaces\, as the nonlinearity of a general ambient space intro duces geometric terms into the classical calculation\, which in general do not carry a sign.\n In this talk we have a look at this situation on the u nit sphere. We prove a concavity maximum principle for a broad class of de generate elliptic equations via a careful analysis of the spherical Jacobi fields and their derivatives. In turn we obtain concavity of solutions to this class of equations. This is joint work with Mat Langford\, Universit y of Tennessee Knoxville.\n\n \n\nFor zoom meeting ID and password please contact dmitry.jakobson [at] mcgill.ca\n DTSTART:20200429T173000Z DTEND:20200429T183000Z SUMMARY:Julian Scheuer (Freiburg) URL:/mathstat/channels/event/julian-scheuer-freiburg-3 21864 END:VEVENT END:VCALENDAR