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VERSION:2.0
PRODID:-//Memento EPFL//
BEGIN:VEVENT
SUMMARY:Non-freeness of certain two-parabolic groups
DTSTART:20190528T160000
DTEND:20190528T170000
DTSTAMP:20260928T184145Z
UID:9a941a4cc8e78befb8e171402e2795a643ca62935d466c06cc8deb42
CATEGORIES:Conferences - Seminars
DESCRIPTION:Sang-Hyun Kim\, KIAS\nFor each positive rational number q\, we
  study the (non-)freeness of the group G(q) generated by 2x2 matrices a = 
 ( (1\,0)\, (1\,1) ) and b = ( (1\,q)\, (0\,1) ) in SL(2\,Q). We give a com
 putational criterion which allows us to prove that if q=s/r for s≤27 the
 n G(q) is non-free\, with the possible exception of s=24. In this latter c
 ase\, we prove that the set of positive integers r for which G(24/r) is no
 n-free has natural density 1. In the course of the proof\, it will follow 
 that for a fixed s\, there are arbitrarily long sequences of consecutive d
 enominators r such that G_(s/r) is non-free. For the case s > 27\, we desc
 ribe a density estimate. (Joint work with Thomas Koberda)
LOCATION:MA B3 514 https://plan.epfl.ch/?room=MAB3514
STATUS:CONFIRMED
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