BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Matthew Conder (University of Auckland) DTSTART:20220701T013000Z DTEND:20220701T023000Z DTSTAMP:20260423T052926Z UID:SiN/43 DESCRIPTION:Title: Dis crete two-generator subgroups of PSL(2\,Q_p)\nby Matthew Conder (Unive rsity of Auckland) as part of Symmetry in Newcastle\n\nLecture held in Lam bert Lounge\, US 321.\n\nAbstract\nDue to work of Gilman\, Rosenberger\, P urzitsky and many others\, discrete two-generator subgroups of PSL(2\,R) h ave been completely classified by studying their action by Möbius transfo rmations on the hyperbolic plane. Here we aim to classify discrete two-gen erator subgroups of PSL(2\,Q_p) by studying their action by isometries on the Bruhat-Tits tree. We first give a general structure theorem for two-ge nerator groups acting by isometries on a tree\, which relies on certain Kl ein-Maskit combination theorems. We will then discuss how this theorem can be applied to determine discreteness of a two-generator subgroup of PSL(2 \,Q_p). This is ongoing work in collaboration with Jeroen Schillewaert.\n LOCATION:https://researchseminars.org/talk/SiN/43/ END:VEVENT END:VCALENDAR