a1 Mathematics Institute, Universitetsparken 5, 2100 Copenhagen ø, Denmark and Department of Mathematics, University of Toronto, Toronto, Canada M5S 1A1
a2 Section de Mathématiques, Université de Genève, CH-1211 Genève 24, Switzerland
A structure theorem is established for amenable actions of a countable discrete group.
(Received February 18 1992)
(Revised September 21 1992)
p1 Present address: Department of Mathematics, University of Ottawa, 585 King Edward, Ottawa, Canada K1N 6N5