BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Vasily Dolgushev (Temple University) DTSTART:20250414T200000Z DTEND:20250414T210000Z DTSTAMP:20260423T040043Z UID:NTBU/24 DESCRIPTION:Title: Ex ploration of Grothendieck-Teichmueller (GT) shadows\nby Vasily Dolgush ev (Temple University) as part of Boston University Number Theory Seminar\ n\nLecture held in CDS Room 365 in Boston University.\n\nAbstract\nIn 1990 \, V. Drinfeld introduced the Grothendieck-Teichmueller group GT.\nThis my sterious group receives a homomorphism from the absolute Galois group $G_Q $\nof rational numbers\, and this homomorphism is injective due to Belyi's theorem. \nGrothendieck-Teichmueller (GT) shadows may be thought of as ap proximations \nof elements of the group GT. They are morphisms of a groupo id whose objects are \ncertain finite index normal subgroups of the Artin braid group. Exploration of the \ngroupoid of GT-shadows is motivated by v ery hard open problems that include \nY. Ihara's question about the surjec tivity of the homomorphism from $G_Q$ to GT.\nIn my talk\, I will introduc e the groupoid of GT-shadows and describe \nits relation to the group GT. I will also present promising results \nand formulate selected open proble ms. My talk is loosely based on joint papers \nwith I. Bortnovskyi\, J.J. Guynee\, B. Holikov and V. Pashkovskyi.\n LOCATION:https://researchseminars.org/talk/NTBU/24/ END:VEVENT END:VCALENDAR