Second cohomology groups and finite covers
Group Theory
2011-03-24 v2 Logic
Abstract
For D an infinite set, k>1 and W the set of k-sets from D, there is a natural closed permutation group G_k which is a non-split extension of \mathbb{Z}_2^W by \Sym(D). We classify the closed subgroups of G_k which project onto \Sym(D)$. The question arises in model theory as a problem about finite covers, but here we formulate and solve it in algebraic terms.
Keywords
Cite
@article{arxiv.0909.0366,
title = {Second cohomology groups and finite covers},
author = {David M. Evans and Elisabetta Pastori},
journal= {arXiv preprint arXiv:0909.0366},
year = {2011}
}
Comments
Typos corrected; change of title to 'Second cohomology groups and finite covers of infinite symmetric groups' in published version