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BEGIN:VEVENT
SUMMARY:Olga Varghese (University of Münster)
DTSTART:20200526T120000Z
DTEND:20200526T130000Z
DTSTAMP:20260404T110745Z
UID:TeaSeminarGeometry/1
DESCRIPTION:Title: Coxeter groups and Kazhdan's property (T)\nby Olga V
arghese (University of Münster) as part of Tea-Seminar: Geometry\, Topolo
gy and Group Theory\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/TeaSeminarGeometry/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jonas Flechsig (University of Bielefeld)
DTSTART:20200609T120000Z
DTEND:20200609T130000Z
DTSTAMP:20260404T110745Z
UID:TeaSeminarGeometry/2
DESCRIPTION:Title: Braids and Artin groups\nby Jonas Flechsig (Universi
ty of Bielefeld) as part of Tea-Seminar: Geometry\, Topology and Group The
ory\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/TeaSeminarGeometry/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pieter Senden (KU Leuven)
DTSTART:20200616T120000Z
DTEND:20200616T130000Z
DTSTAMP:20260404T110745Z
UID:TeaSeminarGeometry/3
DESCRIPTION:Title: The R_infinity property for RAAGs and graph products
\nby Pieter Senden (KU Leuven) as part of Tea-Seminar: Geometry\, Topology
and Group Theory\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/TeaSeminarGeometry/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jens Bossaert (Ghent University)
DTSTART:20200630T120000Z
DTEND:20200630T130000Z
DTSTAMP:20260404T110745Z
UID:TeaSeminarGeometry/4
DESCRIPTION:Title: Expanding the universe of universal groups\nby Jens
Bossaert (Ghent University) as part of Tea-Seminar: Geometry\, Topology an
d Group Theory\n\n\nAbstract\nIn 2000\, Burger and Mozes defined the conce
pt of a universal group acting on a tree with prescribed local actions\, p
roviding interesting examples of totally disconnected locally compact grou
ps. In recent developments their foundational construction has been genera
lised in various ways: Simon Smith studied the topological properties in a
more relaxed setting (where the local actions are not assumed to be trans
itive or of finite degree)\, Adrien Le Boudec introduced "almost-universal
" groups (where one allows for a controlled number of singularities)\, and
Tom De Medts\, Ana Silva and Koen Struyve generalised the original notion
of universal groups to the realm of right-angled buildings. We will discu
ss why right-angled buildings are a natural setting\, try to unify these a
pproaches\, and study how the permutational properties of the local groups
and the combinatorics of the diagram affect the topological properties of
the resulting groups.\n
LOCATION:https://stable.researchseminars.org/talk/TeaSeminarGeometry/4/
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BEGIN:VEVENT
SUMMARY:Corina Ciobotaru
DTSTART:20200707T120000Z
DTEND:20200707T130000Z
DTSTAMP:20260404T110745Z
UID:TeaSeminarGeometry/5
DESCRIPTION:Title: Classical homogeneous dynamics in a non-linear setting\nby Corina Ciobotaru as part of Tea-Seminar: Geometry\, Topology and Gr
oup Theory\n\n\nAbstract\nThe automorphisms group of a bi-regular tree con
tains a rich class of non-linear subgroups G that still share the good pro
perties of the linear ones. Given that\, classical questions from homogene
ous dynamics can be examined and proved. For example\, if H is a discrete
subgroup of G\, recent results show there is a classification of ergodic p
robability measures on G / H that are invariant under horospherical subgro
ups. When H is moreover a cocompact lattice\, the horospherical action is
uniquely ergodic. Or when H is a geometrically finite lattice quantitative
recurrence and equidistribution related to the above probability measures
on G / H hold true. This is a joint project with Vladimir Finkelshtein an
d Cagri Sert.\n
LOCATION:https://stable.researchseminars.org/talk/TeaSeminarGeometry/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alexander Engel (University of Münster)
DTSTART:20201103T130000Z
DTEND:20201103T140000Z
DTSTAMP:20260404T110745Z
UID:TeaSeminarGeometry/6
DESCRIPTION:Title: Compactifications and Combings\nby Alexander Engel (
University of Münster) as part of Tea-Seminar: Geometry\, Topology and Gr
oup Theory\n\n\nAbstract\nAssume that a group G acts freely and cocompactl
y on a contractible space X. If X admits a nice compactification to which
the group action extends continuously\, then many properties of the bounda
ry-at-infinity of X are related to properties of the group G. In this talk
I will firstly give an overview of this setup and corresponding results\,
and secondly discuss how to construct such nice compactifications startin
g from a combing on X.\n
LOCATION:https://stable.researchseminars.org/talk/TeaSeminarGeometry/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Philip Möller (University of Münster)
DTSTART:20201110T130000Z
DTEND:20201110T140000Z
DTSTAMP:20260404T110745Z
UID:TeaSeminarGeometry/7
DESCRIPTION:Title: Abstract group actions of locally compact groups on CAT(
0) spaces\nby Philip Möller (University of Münster) as part of Tea-S
eminar: Geometry\, Topology and Group Theory\n\n\nAbstract\nWe study abstr
act group actions of locally compact Hausdorff groups on CAT(0) spaces. Un
der mild assumptions on the action we show that it is continuous or has a
global fixed point. This mirrows results by Dudley and Morris-Nickolas for
actions on trees. As a consequence we obtain a geometric proof for the fa
ct that any abstract group homomorphism from a locally compact Hausorff gr
oup into a torsion free CAT(0) group is continuous.\n
LOCATION:https://stable.researchseminars.org/talk/TeaSeminarGeometry/7/
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