Quotients by countable normal subgroups are hyperfinite

  • Joshua Frisch

    California Institute of Technology, Pasadena, USA
  • Forte Shinko

    California Institute of Technology, Pasadena, USA
Quotients by countable normal subgroups are hyperfinite cover
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Abstract

We show that for any Polish group and any countable normal subgroup , the coset equivalence relation is a hyperfinite Borel equivalence relation. In particular, the outer automorphism group of any countable group is hyperfinite.

Cite this article

Joshua Frisch, Forte Shinko, Quotients by countable normal subgroups are hyperfinite. Groups Geom. Dyn. 17 (2023), no. 3, pp. 985–992

DOI 10.4171/GGD/719