a Institut de Mathématique, Université de Liège, Sart Tilman Bât. B 37, B-4000 Liege 1, Belgium b Facultad de Matemáticas, Universidad de Valencia, Dr. Moliner 50, E-46100 Burjasot (Valencia), Spain
Abstract:
Given two sequences and of positive numbers, we give necessary and sufficient conditions under which the inclusions