English

Lie-like decompositions of groups definable in o-minimal structures

Logic 2009-12-25 v1

Abstract

There are strong analogies between groups definable in o-minimal structures and real Lie groups. Nevertheless, unlike the real case, not every definable group has maximal definably compact subgroups. We study definable groups G which are not definably compact showing that they have a unique maximal normal definable torsion-free subgroup N; the quotient G/N always has maximal definably compact subgroups, and for every such a K there is a maximal definable torsion-free subgroup H such that G/N can be decomposed as G/N = KH, and the intersection between K and H is trivial. Thus G is definably homotopy equivalent to K. When G is solvable then G/N is already definably compact. In any case (even when G has no maximal definably compact subgroup) we find a definable Lie-like decomposition of G where the role of maximal tori is played by maximal 0-subgroups.

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Cite

@article{arxiv.0912.4753,
  title  = {Lie-like decompositions of groups definable in o-minimal structures},
  author = {Annalisa Conversano},
  journal= {arXiv preprint arXiv:0912.4753},
  year   = {2009}
}

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43 pages