Institution: | (1) Mathematisches Seminar, Christian-Albrechts-Universität, 24118 Kiel, Germany;(2) Department of Mathematics, Oklahoma State University, 74078 Stillwater, Oklahoma, USA;(3) UFR de Mathématiques, Université de Lille Flandres Artois, 59655 Villeneuve d'Ascq, France;(4) Department of Mathematics, Case Western Reserve University, 44106 Cleveland, Ohio, USA |