訂正日: 2006/10/20訂正理由: -訂正箇所: 引用文献情報訂正内容: Wrong : 1) F. DeMeyer and E. Ingraham, Separable algebras over commutative rings, Lecture Notes in Math., 181, Springer, 1971. 2) Y. Doi and M. Takeuchi, Cohomologies over commutative Hopf algebras, J. Math. Soc. Japan, 25 (1973), 680-706. 3) Y. Doi, Homological coalgebra, J. Math. Soc. Japan, 33 (1981), 31-50. 4) K. Hirata, Some types of separable extensions of rings, Nagoya Math. J., 33 (1968), 107-115. 5) K. Sugano, Note on semisimple extensions and separable extensions, Osaka J. Math., 4 (1967), 265-270. 6) M. E. Sweedler, Hopf algebras, Benjamin, New York, 1969.
Right : [1] F. DeMeyer and E. Ingraham, Separable algebras over commutative rings, Lecture Notes in Math., 181, Springer, 1971. [2] Y. Doi and M. Takeuchi, Cohomologies over commutative Hopf algebras, J. Math. Soc. Japan, 25 (1973), 680-706. [3] Y. Doi, Homological coalgebra, J. Math. Soc. Japan, 33 (1981), 31-50. [4] K. Hirata, Some types of separable extensions of rings, Nagoya Math. J., 33 (1968), 107-115. [5] K. Sugano, Note on semisimple extensions and separable extensions, Osaka J. Math., 4 (1967), 265-270. [6] M. E. Sweedler, Hopf algebras, Benjamin, New York, 1969.