訂正日: 2006/08/29訂正理由: -訂正箇所: 引用文献情報訂正内容: Right : [1] S. Ishihara, Homogeneous Riemannian spaces of four dimensions, J. Math. Soc. Japan Vol. 7, (1955), pp. 345-370. [2] K. Iwasawa, On some types of topological groups, Ann. of Math., Vol. 50, (1949), p. 530, Theorem 6. [3] D. Montgomery and H. Samelson, Transformation groups of spheres, Ann, of Math., Vol. 44, (1943), pp. 454-470. [4] K. Nomizu, Invariant affine connections on homogeneous spaces, Amer. J. Math., Vol. 76, (1954), pp. 33-65, [5] K. Yano; On n-dimensional Riemannian spaces admitting a group of motions of order n(n-1)/2+1, Trans. Amer. Math. Soc., Vol. 74, (1953), pp. 260-279. [6] A. G. Walker, The fibring of Riemannian manifolds, Proc. London Math. Soc., Vol. 8, (1953), pp. 1-19.