BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Thomas Hill (University of Warwick) DTSTART:20261015T123000Z DTEND:20261015T133000Z DTSTAMP:20261025T025031Z UID:GaTO/150 DESCRIPTION:Title: M apping class groups of infinite graphs\nby Thomas Hill (University of Warwick) as part of Geometry and topology online\n\nLecture held in Room B 3.02 in the Zeeman Building\, University of Warwick.\n\nAbstract\nThe grou p of topological symmetries of a surface\, known as the mapping class grou p\, provides a powerful lens for studying the geometry and topology of sur faces. The outer automorphism groups of a free group\, $\\operatorname{Out }(F_n​)$\, can be thought of as a graph-theoretic analog of the mapping class group. Although results do not translate directly between the surfa ce and graph settings\, their structural parallels inspire questions and t echniques between these areas. Over the past decade\, there has been a gro wing interest in studying big mapping class groups\, namely those of infin ite-type surfaces. In this talk\, I will discuss recent progress on the a nalog of $\\operatorname{Out}(F_n​)$ for infinite graphs\, including a r igidity theorem\, results about the algebraic properties of their asymptot ically rigid subgroups\, and recent work on actions of these groups on hyp erbolic spaces\, particularly obstructions to general-type actions.\n LOCATION:https://researchseminars.org/talk/GaTO/150/ END:VEVENT END:VCALENDAR