Koji Cho
Kyushu University
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Featured researches published by Koji Cho.
Communications in Mathematical Physics | 2007
Koji Cho; Akito Futaki; Hajime Ono
In [11] it was proved that, given a compact toric Sasaki manifold with positive basic first Chern class and trivial first Chern class of the contact bundle, one can find a deformed Sasaki structure on which a Sasaki-Einstein metric exists. In the present paper we first prove the uniqueness of such Einstein metrics on compact toric Sasaki manifolds modulo the action of the identity component of the automorphism group for the transverse holomorphic structure, and secondly remark that the result of [11] implies the existence of compatible Einstein metrics on all compact Sasaki manifolds obtained from the toric diagrams with any height, or equivalently on all compact toric Sasaki manifolds whose cones have flat canonical bundle. We further show that there exists an infinite family of inequivalent toric Sasaki-Einstein metrics on
Nagoya Mathematical Journal | 1995
Koji Cho; Keiji Matsumoto
International Journal of Mathematics | 2008
Koji Cho; Atsushi Nakayashiki
S^5 sharp k(S^2 times S^3)
Journal of The Mathematical Society of Japan | 2013
Koji Cho; Joe Kamimoto; Toshihiro Nose
International Journal of Mathematics | 2012
Koji Cho; Masaaki Yoshida
for each positive integer k.
Publications of The Research Institute for Mathematical Sciences | 2011
Koji Cho; Andrey A. Mironov; Atsushi Nakayashiki
The beta function B(α, β ) is defined by the following integral where arg , and the gamma function Γ(β ) by where arg .
Kyushu Journal of Mathematics | 1994
Koji Cho; Masaaki Yoshida
The space of Abelian functions of a principally polarized abelian variety (J,Θ) is studied as a module over the ring of global holomorphic differential operators on J. We construct a free resolution in case Θ is non-singular. As an application, in the case of dimensions 2 and 3, we construct a new linear basis of the space of abelian functions which are singular only on Θ in terms of logarithmic derivatives of the higher-dimensional σ-function.
Kyushu Journal of Mathematics | 1995
Koji Cho; Katsuhisa Mimachi; Masaaki Yoshida
The asymptotic behavior at infinity of oscillatory integrals is in detail investigated by using the Newton polyhedra of the phase and the amplitude. We are especially interested in the case that the amplitude has a zero at a critical point of the phase. The properties of poles of local zeta functions, which are closely related to the behavior of oscillatory integrals, are also studied under the associated situation.
Memoirs of The Faculty of Science, Kyushu University. Series A, Mathematics | 1993
Koji Cho; Keiji Matsumoto; Masaaki Yoshida
This paper studies chambers cut out by a special kind of hyperplane arrangements in general position, the Veronese arrangements, in the real projective spaces.
Kumamoto journal of mathematics | 2012
Koji Cho; Kenji Yada; Masaaki Yoshida
The restriction, on the spectral variables, of the Baker-Akhiezer (BA) module of a g-dimensional principally polarized abelian variety with the non-singular theta divisor to an intersection of shifted theta divisors is studied. It is shown that the restriction to a k-dimensional variety becomes a free module over the ring of differential operators in