English

Collineation group as a subgroup of the symmetric group

Group Theory 2017-03-07 v1 Combinatorics

Abstract

Let Ψ\Psi be the projectivization (i.e., the set of one-dimensional vector subspaces) of a vector space of dimension 3\ge 3 over a field. Let HH be a closed (in the pointwise convergence topology) subgroup of the permutation group SΨ\mathfrak{S}_{\Psi} of the set Ψ\Psi. Suppose that HH contains the projective group and an arbitrary self-bijection of Ψ\Psi transforming a triple of collinear points to a non-collinear triple. It is well-known from \cite{KantorMcDonough} that if Ψ\Psi is finite then HH contains the alternating subgroup AΨ\mathfrak{A}_{\Psi} of SΨ\mathfrak{S}_{\Psi}. We show in Theorem \ref{density} below that H=SΨH=\mathfrak{S}_{\Psi}, if Ψ\Psi is infinite.

Keywords

Cite

@article{arxiv.1209.0954,
  title  = {Collineation group as a subgroup of the symmetric group},
  author = {Fedor Bogomolov and Marat Rovinsky},
  journal= {arXiv preprint arXiv:1209.0954},
  year   = {2017}
}

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9 pages