Speaker 
：Motohico Mulase (UC Davis, RIMS ) 
Title 
：SpHitchin Systems and Spinvariant KP Systems 

（Abstract） 
Date 
：March 28 (Fri.) 13:30～15:00 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker 
：Yuichi Nohara ( Dept. of Math., Tohoku Univ. ) 
Title 
：Toric degeneration of flag manifolds and the GelfandCetlin system 

（Abstract） 
Date 
：February 21 (Thu.) 14:40～16:10 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker 
：Hiroshi Iriyeh (Tokyo Denki Univ.) 
Title 
：On the local minimality of geodesics of Hofer's metric. 

（Abstract） 
Date 
：February 21 (Thu.) 13:00～14:30 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker 
：Ryoichi Kobayashi ( Dept. of Math., Nagoya Univ. ) 
Title 
：Ricci flow ancient solutions arising from the natural collapsing
of the twistor space of positive quaternion K\"ahler manifolds 

（Abstract） 
Date 
：February 7 (Thu.) 10:40～12:10 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker 
：Yu Kawakami
(Dept. of Math., Nagoya Univ., Osaka City University Advanced Mathematical
Institute ) 
Title 
：Width and Ricci flow 

（Abstract） 
Date 
：February 6 (Wed.) 14:40～16:10 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker 
：Takumi Yamada ( Dept. of Math., Shimane Univ. ) 
Title 
：Lattice of compact complexparallelizable pseudoKaehler manifolds 

（Abstract） 
Date 
：January 30 (Wed.) 17:15～18:45 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker 
：Yoshihiro Ohnita ( Dept. of Math.,Osaka City Univ. ) 
Title 
：On the deformation of certain 3dimensional minimal Legendrian submanifolds 

（Abstract） 
Date 
：January 23 (Wed.) 14:40～16:10 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker 
：Kazuyoshi Kiyohara ( Dept. of Math., Okayama Univ. ) 
Title 
：The conjugate loci and an asymptotic property of conjugate points on ellipsoids 

（Abstract） 
Date 
：January 16 (Wed.) 14:40～16:10 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker 
：Sadahiro Maeda ( Department of Math., Saga Univ. ) 
Title 
：Homogeneous closed curves on geodesic spheres in a complex
projective space from the viewpoint of submanifold theory 

（Abstract） 
Date 
：December 19 (Wed.) 14:40～16:10 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker 
：Yoo ChulMoon
( Yukawa Institute for Theoretical Physics, Kyoto Univ. ) 
Title 
：Gravitational Lensing in a Clumpy Universe 

（Abstract） 
Date 
：December 12 (Wed.) 17:15～18:15 
Place 
：Dept. of Mathematics, Sci. Bldg., 3068 

Top 

Speaker 
：Yasuo Kurita
( Osaka City University Advanced Mathematical Institute ) 
Title 
：Thermodynamics of fivedimensional black holes with squashed horizons 

（Abstract） 
Date 
：December 12 (Wed.) 16:10～17:10 
Place 
：Dept. of Mathematics, Sci. Bldg., 3068 

Top 

Speaker 
：Masanori Kobayashi ( Dept. of Math., Tokyo Metro. Univ. ) 
Title 
：Elliptic fibration on compact Spin(7)manifolds （after K.Aga) 

（Abstract） 
Date 
：November 28 (Wed.) 17:00～18:30 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker 
：Shouhei Honda ( Dept. of Math., Kyoto Univ. ) 
Title 
：Measure theory on the limit spaces of Riemannian manifolds 

（Abstract） 
Date 
：October 24 (Wed.) 14:40～16:10 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker 
：Daisuke Yamakawa ( Dept. of Math., Kyoto Univ. ) 
Title 
：Moduli of parabolic connections on a Riemann surface with
marked points and representations of quiver 

（Abstract） 
Date 
：October 17 (Wed.) 14:40～16:10 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker 
：Yukinori Yasui ( Dept. of Physics., Osaka City Univ. ) 
Title 
：Closed conformal KillingYano tensor and KerrNUTde Sitter spacetime
uniqueness 

（Abstract） 
Date 
：October 10 (Wed.) 14:40～16:10 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker 
：Miyuki Koiso ( Dept. of Math., Nara Women's Univ. ) 
Title 
：Rolling construction of plane curves and its application to surface theory 

（Abstract） 
Date 
：July 18 (Wed.) 14:40～16:10 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker 
：Tobias Muehlenbruch ( OIST Institute, Okinawa) 
Title 
：Transfer operators for the geodesic billiard for Hecke triangle
groups and the dynamics of continued fractions 

（Abstract） 
Date 
：June 27 (Wed.) 14:40～16:10 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker 
：Yumiko Kitagawa ( Dept. of Math., Nara Women's Univ. ) 
Title 
：On subriemannian contact manifolds 

（Abstract） 
Date 
：June 13 (Wed.) 14:40～16:10 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker 
：Atsushi Kasue ( Dept. of Math., Kanazawa Univ. ) 
Title 
：Convergence of metric graphs and energy forms 

（Abstract） 
Date 
：June 6 (Wed.) 14:40～16:10 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker 
：Yohei Komori ( Dept. of Math., Osaka City Univ. ) 
Title 
：Drawing Bers embeddings of the 1dimensional Teichmuller space 

（Abstract） 
Date 
：May 23 (Wed.) 14:40～16:10 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker 
：Yasufumi Nitta ( Dept. of Math., Osaka Univ. ) 
Title 
：Generalized CalabiYau structures and DuistermaatHeckman theorem 

（Abstract） 
Date 
：May 16 (Wed.) 14:40～16:10 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker 
：Dr. Nahid Sultana (Osaka City University Advanced Mathematical Institute) 
Title 
：Constant mean curvature surfaces of revolution in spherically
symmetric 3manifolds, and their stability 

（Abstract） 
Date 
：April 18 (Wed.) 14:40～16:10 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker 
：Yoshihiro Ohnita (Dept. of Math., Osaka City Univ.) 
Title 
："Classification of homogeneous Lagrangian submanifolds in complex hyperquadrics" 

（Abstract） 
Date 
：April 11 (Wed.) 14:40～16:10 
Place 
：Dept. of Mathematics, Sci. Bldg., 3040 

Top 

Speaker： 
Motohico Mulase (UC Davis, RIMS ) 
Title： 
SpHitchin Systems and Spinvariant KP Systems 
In this informal talk I explain a concrete example of mirror symmetric
pairs of complex manifolds that exhibits StromingerYauZalsow geometric
mirror symmetry. These are obtained as a family of Prym varieties and its
FourierMukai dual family. The total space of the family is an algebraically
completely integrable Hamiltonian system, and the Hamiltonian vector fields
are determined by the (seemingly new) Spinvariant KP flows.
Speaker： 
Yuichi Nohara ( Dept. of Math., Tohoku Univ. ) 
Title： 
Toric degeneration of flag manifolds and the GelfandCetlin system 
It is well known that a polarized toric variety is related to a convex
polytope in two different ways: the moment map and monomial basis. For
a flag manifold $U(n)/T$, we can also associate a certain polytope $\Delta$
in similar ways: the GelfandCetlin system, a completely integrable system;
the GelfandCetlin basis, a basis of an irreducible representation of $U(n)$.
Furthermore, the flag manifold degenerates into the toric variety corresponding
to $\Delta$. KoganMiller proved that the GelfandCetlin basis can be deformed
into a monomial basis on the toric variety under the degeneration. In this
talk we prove that the GelfandCetlin system can be deformed into the moment
map of the toric variety.
Speaker： 
Hiroshi Iriyeh (Tokyo Denki Univ.) 
Title： 
On the local minimality of geodesics of Hofer's metric. 
Hofer's metric on the Hamiltonian diffeomorphism groupof a symplectic manifold
$M$ is a kind of Finsler metric which is defined by Hamiltonian functions
on $M$.
In this talk, we define geodesics of Hofer's metric as critical points
of Hofer's length functions and give a characterization by Hamiltonian
functions, in the case of Hamiltonian diffeomorphism groups (LalondeMcDuff),
in the case of the space of Lagrangian submanifolds (joint work with T.Otofuji).
Next we explain the local minimality following Polterovich's idea via Floer
homology in the case of Hamiltonian diffeomorphism groups.
Speaker： 
Ryoichi Kobayashi ( Dept. of Math., Nagoya Univ. ) 
Title： 
Ricci flow ancient solutions arising from the natural collapsing
of the twistor space of positive quaternion K\"ahler manifolds 
The first part of this lecture is an introduction of Perelman's No Local
Collapsing Theorem (background, proof idea and conclusions) with emphasis
on the Ricci flow "ancient solutions" arising from singularities
of the Ricci flow at finite time. Such ancient solution is extremely important
because it includes all information of the singularity under question.
In the second part, we show that there exists a 2 parameter family of the
Ricci flow ancient solutions on the twistor space of positive quaternion
K\"ahler manifolds. Each of these solutions is (after scaling) asymptotically
K\"ahlerEinstein as $t \to \infty$ and extinct in finite time where
the extinction (after scaling) corresponds to one of the three types of
the natural collapsing of the twistor space. We discuss on application
of these ancnent solutions to the LeBrunSalamon conjecture.
Speaker： 
Yu Kawakami
(Dept. of Math., Nagoya Univ., Osaka City University Advanced Mathematical
Institute ) 
Title： 
Width and Ricci flow 
In this talk, we reveal the relationship between "Width" and
"Ricci flow", prove the result of the finite extinction time
for the Ricci flow on homotopy 3spheres by Tobias H. Colding and William
P. Minicozzi II.
【References】
1. T. H. Colding and W. P. Minicozzi II, Estimates for the extinction time
for the Ricci flow on certain 3manifolds and a question of Perelman, J
Amer. Math. Soc. 18 (2005), 561569.
2. T. H. Colding and W. P. Minicozzi II, Width and finite extinction time
of Ricci flow, preprint, arXiv:0707.0108.
3. G. Perelman, Finite extinction time for the solutions to the Ricci flow
on certain threemanifolds, preprint, math.DG/0307245.
Speaker： 
Takumi Yamada ( Dept. of Math., Shimane Univ. ) 
Title： 
Lattice of compact complexparallelizable pseudoKaehler manifolds 
A complex manifold is called complexparallelizable if the holomorphic
tangent bundle of it is trivial. It is well known that a compact complexparallelizable
manifold is complex homogeneous. In the present talk we introduce a necessary
condition that a compact compact complexparallelizable manifold has a
pseudoKaehler structure.
Speaker： 
Yoshihiro Ohnita ( Dept. of Math.,Osaka City Univ. ) 
Title： 
On the deformation of certain 3dimensional minimal Legendrian submanifolds 
A minimal Legendrian submanifold in a Sasakian manifold is by definition a Legendrian submanifold in a Sasakian manifold which is a minimal submanifold in the sense that its mean curvature vector field with respect to its Sasakian metric vanishes. The minimal Legendrian deformation means a smoooth family of minimal Legendrian submanifolds. In this talk, after we explain the fundamental results on a Legendrian submanifold in a Sasakian manifold such as Legedrian deformation, Legendrian stability, relations with Lagrangian submanifolds etc., we will discuss minimal Legendirian deformations for two examples of $3$dimensional compact minimal Legendrian submanifolds embedded in the $7$dimensional standard $\eta$Einstein Sasakian manifolds.
Speaker： 
Kazuyoshi Kiyohara ( Dept. of Math., Okayama Univ. ) 
Title： 
The conjugate loci and an asymptotic property of conjugate points on ellipsoids 
This is a joint work with Jinichi Itoh.
It is well known that the geodesic flow of any ellipsoid is completely
integrable in the sense of hamiltonian mechanics. In this talk, we would
like to discuss much finer properties of the behavior of geodesics. In
particular, we shall show that the conjugate locus of a general point contains
just three connected components of singularities, each of which is a cuspidal
edge (n>2). This result is a higher dimensional version of "the
last geometric statement of Jacobi", which asserts that the conjugate
locus of a general point on any twodimensional ellipsoid contains just
four cusps. Also, we shall show that the distribution of the conjugate
points along a general geodesic possesses an interesting asymptotic property.
The above results also hold for some Liouville manifolds.
Speaker： 
Sadahiro Maeda ( Department of Math., Saga Univ. ) 
Title： 
Homogeneous closed curves on geodesic spheres in a complex
projective space from the viewpoint of submanifold theory 
It is known that every geodesic on each geodesic sphere in a complex projective space is a homogeneous curve, that is, every geodesic is an orbit under a certain oneparameter subgroup of the isometry group of the geodesic sphere. In this talk, we give a family of homogeneous nongeodesic closed curves on this geodesic sphere through submanifold theory.
Speaker： 
Yoo ChulMoon
( Yukawa Institute for Theoretical Physics, Kyoto Univ. ) 
Title： 
Gravitational Lensing in a Clumpy Universe 
According to recent observation and theoretical studies, 99% of the mass
in our universe is not luminous. Therefore, in order to investigate the
all of the inhomogeneities in our universe, we have to know the distribution
of the "dark components". Consequently, gravitational lensing
effects are focused on as a means of observation of the dark matter distribution.
Gravitational lensing effects are General relativistic effects on light
rays which are induced by the matter distribution on the ray path. In this
talk, first, I will give an explanation of these effects with a focus on
the geometry of the ray bundle. Then, I will talk about our work in which
we have studied multiple lensing effects on the light rays from point sources.
Speaker： 
Yasuo Kurita
( Osaka City University Advanced Mathematical Institute ) 
Title： 
Thermodynamics of fivedimensional black holes with squashed horizons 
In the fivedimensional Einstein gravity, there exist black hole solutions
with squashed horizons. In general, black holes have thermodynamical nature
because they are characterized by the irreversibility. After giving a brief
review of black holes and thermodynamics from the viewpoint of theoretical
physics, I will talk about thermodynamics of the fivedimensional black
holes with squashed horizons.
Speaker： 
Masanori Kobayashi ( Dept. of Math., Tokyo Metro. Univ. ) 
Title： 
Elliptic fibration on compact Spin(7)manifolds （after K.Aga) 
Compact SU(4)manifold with elliptic fibration interested in from the point
of view from string theory. In this talk we treat compact Spin(7)manifolds,
which do not have complex structure, nevertheless with elliptic fibration
mainly after the master thesis of Kiichiro Aga (TMU).
Speaker： 
Shouhei Honda ( Dept. of Math., Kyoto Univ. ) 
Title： 
Measure theory on the limit spaces of Riemannian manifolds 
M.Gromov showed; the set of Riemannian manifolds whose Ricci curvatures
have a definite lower bound, is precompact with respect to the GromovHausdorff
distance. Recently, many important results for the GromovHausdorff limit
spaces of such Riemannian manifolds were shown by J.Cheeger, T.H.Colding.
In this talk, we study some measure theoritic results for such spaces with
related to the works of them.
Speaker： 
Daisuke Yamakawa ( Dept. of Math., Kyoto Univ. ) 
Title： 
Moduli of parabolic connections on a Riemann surface with
marked points and representations of quiver 
In this talk, I will describe a moduli space of parabolic connections on
a Riemann surface with marked points as a certain analogue of a quiver
variety. This variety is constructed as a "groupvalued" holomorphic
symplectic quotient and has many similarities to a quiver variety.
Speaker： 
Yukinori Yasui ( Dept. of Physics., Osaka City Univ. ) 
Title： 
Closed conformal KillingYano tensor and KerrNUTde Sitter spacetime uniqueness 
Higher dimensional black hole solutions have attracted renewed interests
in the recent developments of supergravity and superstring theories. Recently,
the ddim. Kerr NUTde Sitter metrics were constructed by ChenLuPope.
All the known vacuum type D black hole solutions are included in these
metrics. In this talk we study spacetimes with a conformal KillingYano
tensor. It is shown that the KerrNUTde Sitter spacetime is the only spacetime
admitting a rank2 closed conformal KillingYano tensor with a certain
symmetry.
Speaker： 
Miyuki Koiso ( Dept. of Math., Nara Women's Univ. ) 
Title： 
Rolling construction of plane curves and its application to surface
theory 
We give a new geometric description of the rolling curve of a general plane
curve and apply it to the generating curves of anisotropic Delaunay surfaces.
For example, the rolling curve of the generating curve of an anisotropic
unduloid or nodoid S is obtained as a type of `dual curve' of a `mean curvature
profile' of S. Here, a mean curvature profile of S is a curve whose curvature
is equal to twice the mean curvature of S. This generalizes the classical
construction for rotationally symmetric surfaces with constant mean curvature
due to Delaunay.
Speaker： 
Tobias Muehlenbruch ( OIST Institute, Okinawa) 
Title： 
Transfer operators for the geodesic billiard for Hecke triangle
groups and the dynamics of continued fractions 
After introducing Hecke triangle groups and the associated geodesic billiard,
I show a discretization, relating periodic orbits on the geodesic billiard
to periodic continued fraction expansions of points. This allows us to
describe the dynamics on the billiard system by understanding the discrete
dynamics related to the continued fractions. The continued fractions are
the so called nearest $\lambda$integer continued fractions. Hurwitz already
studied these fractions for $\lambda =1$.
Speaker： 
Yumiko Kitagawa ( Dept. of Math., Nara Women's Univ. ) 
Title： 
On subriemannian contact manifolds 
A subriemannian manifold (M,D,g) is a differential manifold M equipped
with a subbundle D of the tangent bundle TM of M and a riemannian metric
g on D. In particular, it is called a subriemannian contact manifold if
D is a contact structure, i.e., a subbundle of codimension 1 and nondegenerate.
In this talk we study the structure of infinitesimal automorphisms of a
subriemannian contact manifold.
Speaker： 
Atsushi Kasue ( Dept. of Math., Kanazawa Univ. ) 
Title： 
Convergence of metric graphs and energy forms 
Some aspects of infinite networks will be discussed from a view point of
convergence of finite networks with respect to the topology of both the
GromovHausdorff distance and variational convergence called $\Gamma$convergence.
Speaker： 
Yohei Komori ( Dept. of Math., Osaka City Univ. ) 
Title： 
Drawing Bers embeddings of the 1dimensional Teichmuller space 
We present a computeroriented method of producing pictures of Bers embeddings
of the 1dimensional Teichmuller space. Our algorithm consists of two steps;
we first compute the monodromy representation of Schwarzian differential
equation by numerical integral. Then we decide whether the monodromy group
is discrete by applying Jorgensen's theory on the quasiFuchsian space
of oncepunctured tori. This is a joint work with Toshiyuki Sugawa (Hiroshima),
Masaaki Wada(Nara) and Yasushi Yamashita(Nara).
Speaker： 
Yasufumi Nitta ( Dept. of Math., Osaka Univ. ) 
Title： 
Generalized CalabiYau structures and DuistermaatHeckman theorem 
This talk is about generalized complex structures. This is a new kind of
geometrical structure introduced by Hitchin and developed by Gualtieri,
which contains complex and symplectic geometry as its extremal special
cases. In the present talk, we shall introduce the reduction theorem for
a group action on generalized complex manifolds. Moreover we shall explain
that the DuistermaatHeckman theorem holds in the case of generalized CalabiYau
manifolds.
Speaker： 
Dr. Nahid Sultana (Osaka City University Advanced Mathematical Institute) 
Title： 
Constant mean curvature surfaces of revolution in spherically
symmetric 3manifolds, and their stability 
We compute explicit conformal parametrizations of Delaunay surfaces in
$\mathbb{R}^3$, $\mathbb{S}^3$ and $\mathbb{H}^3$ by using the generalized
Weierstrass type representation for CMC surfaces. By using these explicit
parametrizations, we introduce the explicit area formula for the fundamental
pieces of Delaunay surfaces. When Delaunay surfaces in $\mathbb{S}^3$ close
to become tori, we can study their Morse index. The Morse index of general
closed CMC surfaces of revolution in $\mathbb{S}^3$ is still unknown. Hence,
we compute lower bounds for the Morse index and nullity of CMC tori of
revolution in $\mathbb{S}^3$. To test the sharpness of the lower bounds,
we numerically compute the eigenvalues of the Jacobi operator. Furthermore,
we study the stability properties of CMC surfaces of revolution in general
simplyconnected spherically symmetric $3$spaces, and in particular case
a positivedefinite $3$dimensional slice of Schwarzschild space.
Speaker： 
Yoshihiro Ohnita (Dept. of Math., Osaka City Univ.) 
Title： 
"Classification of homogeneous Lagrangian submanifolds in complex hyperquadrics" 
This talk is based on my recent joint work with Hui Ma (Tsinghua University,
Peking). The $n$dimensional complex hyperquadric $Q_{n}({\bold C})$ is
a compact complex algebraic hypersurface defined by the quadratic equation
$z_{0}^{2}+z_{1}^{2}+\cdots+z_{n}^{2}+z_{n+1}^{2}=0$ in the $(n+1)$dimensional
complex projective space, which is isometric to the real Grassmann manifold
of oriented $2$dimensional vector subspaces of ${\bold R}^{n+2}$. It is
a compact Hermitian symmetric space of rank $2$. In this talk we provide
a classification of compact homogeneous Lagrangian submanifolds, i.e. Lagrangian
orbits of compact Hamiltonian group actions, in complex hyperquadrics by
using the moment map technique from the viewpoint of homogeneous isoparametric
hypersurface geometry in spheres. We showed that any compact homogeneous
Lagrangian submanifold in complex hyperquadrics is obtained as the Gauss
image of a homogeneous isoparametric hypersurface in a sphere or certain
oneparameter families of Lagrangian orbits in $Q_{n}({\bold C})$.
Last Modified on Maech 26, 2008.
All Rights Reserved, Copyright (c) 20032005 Department of Mathematics, OCU 
