Institution: | Department of Mathematics, University of Washington, Seattle WA 98195 USA;Institut Francaise du Petrol, B. P. 311, 92506 Rueil-Malmaison Cedex, France;Department of Mathematics, Iowa State University, Ames, IA 50011, USA;Department of Mathematical Sciences, University of Delaware, Newark, DE 19716, USA;Department of Mathematical Sciences, Rice University, Houston, TX 77251, USA |