Sendai Max Dehn seminar
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Marc Bourdon(Univ Lille)
An algebraic characterisation of quasi-Moebius homeomorphisms
2006.10.20(Fri) 3-4pm. at Sugaku-203
Satoshi Ishiwata (Tsukuba U)
Connectivity of discrete nilpotent groups
2006.11.29(wed). 1:30-2:30. C-316.
" Homotopy of ends and boundaries of CAT(0) groups"
G. Conner, M. Mihalik and S. Tschantz
2005.6.16(Th) at C-316.
Dr.Kenneth J.Shackleton (U of Southampton).
2:00-3:30. "Tight geodesics and computing distances in the curve complex."
"Curve complex embeddings and injections of mapping class groups."
2005.5.12. 2-3pm, 3:30-4:30pm. at C-316.
Brian Bowditch (U of Southampton, TIT)
"Geometry of curve compexes and hyperbolic 3-manifolds".
2004.8.17(Tue). at 518.
Mark Sapir (Vanderbilt Univ)
"Asymptotic cones of relatively hyperbolic groups and quasi-isometry
2004.7.21 (Wed). (1) 3-4pm, (2) 4:30-5:30pm. $B?t3XEo(B
Calegari (Cal Tech).
- 3-4pm. "Dynamical forcing of circular groups".
abstract: Given a pair (G,a)
where G is a group, and a is an element of G, define X(G,a)
to be the subset of S1 consisting of all rotation numbers of
a under homomorphisms from G to Homeo^+(S1). We show that the
set of subsets of this form are exactly the subsets which
contain 0, are invariant under x -> -x, and are closed.
We also show that all such subsets can be approximated in
a certain sense by restricting to (explicit) finitely presented
- 4:30-5:30pm. "Universal circles for quasigeodesic flows".
is a closed hyperbolic 3-manifold with a quasigeodesic flow.
Then pi_1(M) acts faithfully on a circle by homeomorphisms,
and preserves a pair of laminations of this circle. As a
corollary, the unit ball of the Thurston norm can be
detected by quasigeodesic flows (generalizing a theorem of
Mosher) and there are infinitely many hyperbolic 3-manifolds
without quasigeodesic flows, answering a question of Thurston.
2004.6.11. $B!J6b!K(B.2-3pm. $B?t3XEo(B518
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2004.5.27.($BLZ(B). 3-4pm. C$BEo(B-316.
"Splitting theorems for CAT(0) spaces"
2004.5.20($BLZ(B). 3-4pm. C$BEo(B-316.
the talk is supported partially by the COE program
"Exploring New Science by Bridging Particle-Matter Hierarchy".
2:00-3:30 $B?t3XEo(B418(changed to 518)
Yann Ollivier (Univ Paris Sud)
Peter Brinkmann(Univ of Illinois)
"Dynamics of free group automorphisms"
Abstract : We present a coarse convexity result for the dynamics of
automorphisms of finitely generated free groups.
As an application, we obtain an algorithm that detects
whether two elements of the free group are contained
in the same orbit of a given automorphism.