| Speaker |
Ruth Kellerhals (University of Fribourg, OCAMI) |
| Title |
Some new developments on hyperbolic space forms in dimension 5 |
| Date |
Mar. 21 (Wed.) 2012, 17：00～18：00 |
| Place |
Dept. of Mathematics, Sci.Bldg., 3040 |
| Abstract |
After a short introduction to hyperbolic orbifolds, simple constructions and properties, we consider those with many symmetries and try to rank them by means of their volumes. We discuss known
results in dimensions below five and present then new developments for hyperbolic 5-orbifolds by restricting ourselves to the arithmetic, oriented case. This is joint work with Vincent Emery (MPI Bonn).
|
| Speaker |
Hiroyuki OCHIAI (Institute of Mathematics for Industry, Kyushu University) |
| Title |
対称対の有限型２重旗多様体 |
| Date |
Jan. 25 (Wed.) 2012, 16：30～17：30 |
| Place |
Dept. of Mathematics, Sci.Bldg., 3040 |
| Abstract |
Japanese version only
|
| Speaker |
Athanase Papadopoulos (Strasbourg University, France) |
| Title |
Teichmüller spaces of surfaces of infinite type |
| Date |
Dec. 7 (Wed.) 2011, 16：30～17：30 |
| Place |
Dept. of Mathematics, Sci.Bldg., 3040 |
| Abstract |
I will describe some topological and metrical properties of Teichmüller spaces of surfaces of infinite type, highlighting the differences with those of Teichmüller spaces of surfaces of finite type.
|
| Speaker |
Shigeaki KOIKE (Saitama University) |
| Title |
完全非線形方程式のABP最大値原理の最近の進展 |
| Date |
Nov. 30 (Wed.) 2011, 16：30～17：30 |
| Place |
Dept. of Mathematics, Sci.Bldg., 3040 |
| Abstract |
Japanese version only
|
| Speaker |
Megumi HARADA (McMaster University) |
| Title |
Finite group quotients among symplectic toric Deligne-Mumford stacks |
| Date |
Nov. 22 (Tue.) 2011, 17：00～18：00 |
| Place |
Dept. of Mathematics, Sci.Bldg., 3040 |
| Abstract |
Let $\Delta$ be a Delzant polytope in $\mathbb{R}^n$. The classical Delzant construction associates to $\Delta$ a compact symplectic manifold equipped with an effective Hamiltonian $T^n$-action,
via a symplectic quotient construction. The algebro-geometric analogue of this construction is the Cox construction of toric varieties, where here the combinatorial input is the data of a fan $\Sigma$ and
uses a GIT quotient. These spaces which are equipped with large torus actions provide a rich class of examples in many areas of mathematics. More recently, Borisov-Chen-Smith extended the Cox
construction in the context of stack quotients, where now the combinatorial input is a so-called stacky fan and the output is the so-called toric Deligne-Mumford (DM) stack. The analogous
symplectic-geometric construction uses polytopes equipped with the additional data of a labelling. As with their classical (non-stacky) counterparts, toric DM stacks promise to be a fertile source of
examples on which to test general theories associated to stacks. In this talk I will first quickly review these stacky constructions and in particular relate the symplectic and algebro-geometric points of view.
Second, I will discuss joint work in progress with Krepski and Goldin-Johannsen-Krepski which is motivated by the stack analogue of the following classical topological question: when is a topological space
realizable as a quotient of a smooth manifold by a \emph{finite} group action? In our context, at least in a special case, the answer turns out to be quite concrete, explicit, and elegantly stated in terms of
the defining combinatorics.
|
| Speaker |
Krzysztof Pawalowski (UAM, Poznan', Poland) |
| Title |
Smooth vs. symplectic actions on complex projective spaces |
| Date |
Nov. 17 (Thu.) 2011, 16：30～17：30 |
| Place |
Dept. of Mathematics, Sci.Bldg., 3040 |
| Abstract |
The goal of the talk is to present a difference between arbitrary smooth actions of compact Lie groups G on complex projective spaces and these actions which preserve some additional structures on the
spaces, such as K\"ahler, symplectic, complex, or almost complex. Our results show that in general the additional structures are not preserved by smooth actions of G on complex projective spaces. If an
action of G preserves one of the additional structures above, the fixed point set F is a manifold which admits the given structure. We prove that the specific structure on F may be missing in general. For
an appropriate group G, it may even happen that any closed smooth manifold F occurs as the fixed point set of a smooth action of G on some complex projective space.
|
| Speaker |
Atsushi KASUE (Kanazawa University) |
| Title |
無限ネットワークのランダムウォークと倉持境界 |
| Date |
June 8 (Wed.) 2011, 16：30～17：30 |
| Place |
Dept. of Mathematics, Sci.Bldg., 3040 |
| Abstract |
Japanese version only
|
| Speaker |
Yoshie SUGIYAMA (Osaka City University) |
| Title |
Keller-Segel系の解の構造について |
| Date |
Apr. 20 (Wed.) 2011, 16：30～17：30 |
| Place |
Dept. of Mathematics, Sci.Bldg., 3040 |
| Abstract |
Japanese version only |
Last Modified on 2015.11.24
