BEGIN:VCALENDAR VERSION:2.0 PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4// BEGIN:VEVENT UID:20260621T060445EDT-0420kKdVao@132.216.98.100 DTSTAMP:20260621T100445Z DESCRIPTION:Title:2-Systems of arcs on spheres with prescribed endpoints.\n \nAbstract: A 2-system of arcs on an n-punctured sphere S is a collection of (homotopy classes of) simple arcs on S joining punctures and pairwise i ntersecting at most twice. Bar-Natan proved that a 2-system of arcs on S b eginning and ending at a fixed puncture has size at most n choose 3. In th is talk\, I will sketch a proof that the same holds for a 2-system of arcs on S joining a fixed pair of distinct punctures.\n DTSTART:20190227T200000Z DTEND:20190227T210000Z LOCATION:Room 920\, Burnside Hall\, CA\, QC\, Montreal\, H3A 0B9\, 805 rue Sherbrooke Ouest SUMMARY:Sami Douba\, 91ºÚÁÏÍø URL:/mathstat/channels/event/sami-douba-mcgill-univers ity-294932 END:VEVENT END:VCALENDAR