訂正日: 2006/09/29訂正理由: -訂正箇所: 引用文献情報訂正内容: Right : [1] L. P. Eisenhart, Continuous group of transformations, Princeton, 1933. [2] S. Tachibana, On Killing tensors in a Riemannian space, to appear. [3] K. Yano, Some remarks on tensor fields and curvature, Ann. of Math., 55 (1952),328-347. [4] K. Yano and S. Bochner, Curvature and Betti numbers, Ann. of Math. Studies. No. 32, 1953.