訂正日: 2006/09/26訂正理由: -訂正箇所: 引用文献情報訂正内容: Right : [1] M. Ako, Submanifolds in Fubinian manifolds, Kodai Math. Sem. Rep., 19 (1967), 103-128. [2] M. Obata, Certain conditions for a Riemannian manifold to be isometric with a sphere, J. Math. Soc. Japan, 14 (1962), 333-340. [3] M. Okumura, Totally umbilical hypersurfaces of a locally product Riemannian manifold, Kodai Math. Sem. Rep., 19 (1967), 35-42. [4] J. A. Schouten and K. Yano, On invariant subspaces in the almost complex X2n, Indag. Math., 17 (1953), 261-269. [5] Y. Tashiro, Complete Riemannian manifolds and some vector fields, Trans. Amer. Math. Soc., 117 (1965), 251-275. [6] K. Yano, Concircular geometry I-V, Proc. Imp. Acad. Japan, 16 (1940), 195-200, 354-360, 442-448, 505-511, 18 (1942), 446-451.
