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) G. Hochschild and J. -P. Serre, Cohomology of group extensions, Trans. Amer. Math. Soc. 74 (1953), pp. 110-134. 2) See, S. Eilenberg and S. MacLane, Cohomology theory in abstract groups. I, Ann. of Math. 48, (1947), pp. 51-78, and G. Hochschild and J. -P. Serre, loc. cit. in 1). 3) See Appendix. 4) G. Hochschild and J. -P. Serre, loc. cit., Chap. III, §4, Theorem 2. 5) G. Hochschild and J. -P. Serre, loc. cit., Chap. III, 6, Theorem 3. 7) Chap. II, §3. 8) The homology and the cohomology theory can be built up based on a few fundamental properties of tensor product and the group of homomorphisms, as is shown e. g. in S. Eilenberg and N. Steenrod, Foundations of algebraic topology. Princeton University Press, 1952. Homg (B⊗η A, C)≅Homη (A, Homg (B, C)) is one of them, where A is an η-module, C a g-module and B a (g, η)-double module. 9) Z(g) is considered as a right g-module by the right multiplication. 10) Cf. S. Eilenberg and S. MacLane, On the groups H (II, n), I. Ann. of Math. 58 (1953), pp. 55-106, where the case of abelian groups is treated.