BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Kathryn Mann (Cornell University) DTSTART:20201104T200000Z DTEND:20201104T210000Z DTSTAMP:20260513T195536Z UID:McGillGGT/9 DESCRIPTION:Title: Stability for hyperbolic groups acting on their boundaries\nby Kathr yn Mann (Cornell University) as part of McGill geometric group theory semi nar\n\n\nAbstract\nA hyperbolic group acts naturally by homeomorphisms on its boundary. The theme of this talk is to say that\, in many cases\, suc h an action has very robust dynamics. \n\nJonathan Bowden and I studied a very special case of this\, showing if G is the fundamental group of a co mpact\, negatively curved Riemannian manifold\, then the action of G on it s boundary is topologically stable (small perturbations of it are semi-con jugate\, containing all the dynamical information of the original action). In new work with Jason Manning\, we get rid of the Riemannian geometry an d show that such a result holds for hyperbolic groups with sphere boundary \, using purely large-scale geometric techniques. \n\nThis theme of study ing topological dynamics of boundary actions dates back at least as far as work of Sullivan in the 1980's\, although we take a very different approa ch. My talk will give some history and some picture of the large-scale ge ometry involved in our work.\n LOCATION:https://researchseminars.org/talk/McGillGGT/9/ END:VEVENT END:VCALENDAR