a1 Institut des Hautes Etudes Scientifiques, 35 route de Chartres, 91440 Bures-sur-Yvette, France
a2 Department of Mathematics, University of California at Berkeley, California, USA
a3 Hebrew University of Jerusalem, Israel
We prove that for any amenable non-singular countable equivalence relation RX×X, there exists a non-singular transformation T of X such that, up to a null set:
It follows that any two Cartan subalgebras of a hyperfinite factor are conjugate by an automorphism.
(Received May 25 1981)
(Revised September 01 1981)