Contraction groups in complete Kac-Moody groups

  title={Contraction groups in complete Kac-Moody groups},
  author={Udo Baumgartner and J. Ramagge and Bertrand R{\'e}my},
Let G be an abstract Kac-Moody group over a finite field and G the closure of the image of G in the automorphism group of its positive building. We show that if the Dynkin diagram associated to G is irreducible and neither of spherical nor of affine type, then the contraction groups of e lem nts inG which are not topologically periodic are not closed. (In those gro ups there always exist elements which are not topologically periodic.) Mathematics Subject Classification (2000)contraction group… CONTINUE READING