| April 11 |
2:30 - 4:00
RIMS 204 |
Rui Okayasu (Osaka Kyoiku University)
Free group $\mathrm{C}^*$-algebras associated with $\ell_p$
For every $p\geq 2$, we give a characterization of positive definite
functions on a free group, which can be extended to the positive linear
functionals on the free group $\mathrm{C}^*$-algebra associated with $\ell_p$. As
a consequence, the associated $\mathrm{C}^*$-algebras are mutually non-isomorphic,
and they have a unique tracial state.
|
| |
| April 18 |
2:30 - 4:00
RIMS 204 |
Hiroki Sako (RIMS)
Property A and the operator norm localization property for discrete metric spaces
We study property A defined by Yu and the operator norm localization
property defined by Chen, Tessera, Wang, and Yu. These are coarse
geometric properties for metric spaces, which have applications to
operator K-theory. It is proved that these two properties are equivalent
for discrete metric spaces with bounded geometry. Combining this theorem
with a recent result by Brodzki, Niblo, Spakula, Willett, and Wright, we
obtain several characterizations of property A.
|
| |
| May 02 |
2:30 - 4:00
RIMS 204 |
Narutaka Ozawa (RIMS)
Cantor minimal systems and finitely generated simple amenable groups
(after Matui, Juschenko--Monod)
Juschenko and Monod proved the Grigorchuk--Medynets conjecture that
the topological full groups of any minimal transformation on the Cantor space is amenable.
It was previously known that the commutator subgroup of such a group is simple
(Bezuglyi--Medynets and Matui) and sometimes finitely generated (Matui).
Thus, these groups give rise to the first examples
of infinite finitely generated groups that are simple and amenable.
I will discuss these results and their background.
|
May 02
Colloquium |
4:30 - 5:30
RIMS 110 |
Andrzej Żuk (Paris VI & RIMS)
On a problem of Atiyah
In 1976, Michael Atiyah defined $L^2$-Betti numbers for manifolds and
asked a question about their rationality. These numbers arise as the von Neumann
dimensions of kernels of certain operators acting on the $L^2$-space of the fundamental
group of a manifold. The problem concerning their values is closely related to
the Kaplansky zero-divisor question. We present constructions of closed manifolds
with irrational $L^2$-Betti numbers.
|
| |
| May 16 |
2:30 - 4:00
RIMS 204 |
Mamoru Tanaka (RIMS)
Expander graphs and higher eigenvalues of the Laplacians on graphs
In words, expander graphs are highly connected sparse graphs. They are
used in theoretical computer science, combinatorics, functional analysis,
and so on. It is known that expander graphs are characterized by the
second eigenvalues of the Laplacians on the graphs. In this talk, we give
relations between expander graphs and higher eigenvalues of the Laplacians
on graphs.
|
| |
| May 26 |
RIMS 420 |
Takagi Lectures
|
| |
May 28 -
- June 01 |
RIMS 111
RIMS 420 |
Developments of the geometry of transformation groups
Conference on Geometry
|
| |
| June 04 - 08 |
RIMS 420 |
Geometric Group Theory - Kyoto 2012 |
| |
| June 20 |
2:30 - 4:00
RIMS 204 |
TBA (TBA)
TITLE
ABSTRACT HERE.
|
June 20
Colloquium |
4:30 - 5:30
RIMS 110 |
Igor Mineyev (UIUC & RIMS)
TBA
TBA.
|
| |
June 27
Enlarged Colloquium |
2:40 - 3:40
&
4:30 - 5:30
RIMS 420 |
TBA (TBA)
TITLE
ABSTRACT HERE.
TBA (TBA)
TITLE
ABSTRACT HERE.
|
| |
| July 04 |
2:30 - 4:00
RIMS 204 |
TBA (TBA)
TITLE
ABSTRACT HERE.
|
| |
| July 18 |
2:30 - 4:00
RIMS 204 |
TBA (TBA)
TITLE
ABSTRACT HERE.
|
| |