A note on finite group 1-cohomology via semi-direct products with applications to permutation modules

Section 17 of the important textbook [1] of M. Aschbacher studies Finite Group 1-Cohomology with a field coefficient ring via semi-direct products. This approach yields new structures and results to this basic subject. Here we assume that the coefficient ring is any commutative ring and we obtain all of the results of [1, Section 17] excluding Theorem 17.12. Via duality, this theorem extends the previous main result Theorem 17.11. In our final main results we assume that the coefficient ring is a discrete valuation ring, so that [1, Theorem 17.12] is a special case. Thus all of our results are applicable to Finite Group Modular Representation Theory. We conclude with applications to finite group permutation modules. Mathematics Subject Classification: 20J06