
7 Acknowledgements
It is our great pleasure to thank Shuhei Mano, Yasushi Mino,
Takashi Nakamura, Eric Poisson, Masaru Shibata, Eiichi Takasugi,
and Takahiro Tanaka for collaborations and fruitful discussions. We
are grateful to Luc Blanchet and Bala Iyer for useful suggestions
and comments. We are also grateful to Ryuichi Fujita for checking
formulae in the draft. This work was supported in part by
Grant-in-Aid for Scientific Research, Nos. 14047214 and
12640269, of the Ministry of Education, Culture, Sports, Science,
and Technology of Japan.
