Superrigidity and countable Borel equivalence relations Original Research Article

We formulate a Borel version of a corollary of Furmanʹs superrigidity theorem for orbit equivalence and present a number of applications to the theory of countable Borel equivalence relations. In particular, we prove that the orbit equivalence relations arising from the natural actions of View the MathML source on the projective planes over the various p-adic fields are pairwise incomparable with respect to Borel reducibility.