Affiliation: | 1. LIX, École Polytechnique, 91128 Palaiseau Cedex-France;2. LIAFA (Université Paris Diderot), 2 place Jussieu 75251 Paris cedex 05;1. Stanford University, Department of Mathematics, building 380, Stanford, CA 94305, USA;2. University of California, San Diego, Department of Mathematics, 9500 Gilman Dr. #0112, San Diego, CA 92093, USA |