BEGIN:VCALENDAR VERSION:2.0 PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4// BEGIN:VEVENT UID:20250813T003102EDT-4104UwPna0@132.216.98.100 DTSTAMP:20250813T043102Z DESCRIPTION:Title: Sums of two cubes.\n\nAbstract: I'll give an overview of recent work with Alpoge-Bhargava showing that at least 10/21 (resp. 1/6) of integers are (resp. are not) a sum of two rational cubes. To prove this \, we first show that the average size of the 2-Selmer group in any cubic twist family of elliptic curves is 3\, by reducing to a certain counting p roblem: count integral G-orbits in a G-invariant quadric inside V\, where G = SL_2^2 and V is the space of pairs of binary cubic forms. To perform t he lattice point count\, we combine tools from geometry of numbers and the circle method.  My talk will focus on the more algebraic aspects of the p roblem\, e.g.: how one reduces to the counting problem\, and how one deduc es the results about sums of two cubes from the Selmer average result. If I have time\, I'll explain a result for cubic twist families of higher dim ensional abelian varieties as well.\n DTSTART:20221027T143000Z DTEND:20221027T160000Z LOCATION:Room 1104\, Burnside Hall\, CA\, QC\, Montreal\, H3A 0B9\, 805 rue Sherbrooke Ouest SUMMARY:Ari Shnidman (Hebrew University of Jerusalem) URL:/mathstat/channels/event/ari-shnidman-hebrew-unive rsity-jerusalem-342993 END:VEVENT END:VCALENDAR