THE NONTRIVIALITY OF THE RESTRICTION MAP IN THE COHOMOLOGY OF GROUPS

@inproceedings{Swan1960THENO,
  title={THE NONTRIVIALITY OF THE RESTRICTION MAP IN THE COHOMOLOGY OF GROUPS},
  author={Richard G. Swan},
  year={1960}
}
An unpublished result2 of B. Mazur states that if ir is any nontrivial finite group then there is an i> 0 such that Hi(Qr, Z) $0. It is, course, trivial that Hi(ir, A) #0 for some ir-module A. The point of Mazur's theorem is that we can even take A = Z, the ring of integers with trivial ir-action. Mazur's proof of this theorem is geometric. It involves imbedding ir in a compact Lie group G and studying the Leray-Cartan spectral sequence of the covering G-*G/ir. The purpose of this paper is to… CONTINUE READING