Université Bordeaux I, Laboratoire de Mathématiques Pures, 351 cours de la Libération, F-33405 Talence Cedex 05, France - Steklov Mathematical Institute, St. Petersburg Branch, Fontanka 27, 191011 St. Petersburg, Russia
Abstract:
For a positive function on the unit circle with , the following two statements are equivalent: (a) ; (b) there is an operator projecting onto for all at once and having weak type (1,1) with respect to .