Maugeri, AVenkatesha Murthy, M KTrudinger, Neil2015-12-100925-5001http://hdl.handle.net/1885/56863Some of the papers and lectures devoted to the memory of Sergio Campanato and Guido Stampacchia, delivered during the International Conference titled 'Variational Analysis and Partial Differential Equations' held on 5-14 July 2006 are presented. The regularization theory was one of the predominant interests of Sergio Campanato, and he was concerned with the way of finding a general regularization methodology from which the regularity results in all the tough situations could be derived. He developed a methodology in which one has to study the ratio of the Lp norms on concentric balls of different radii of a solution of a class of second order differential systems depends on the ratio of the radii. Sergio searched solutions for partial differential equations by showing the existence of a unique solution of the Dirichlet problem in the class W2,p(Ω), p∈ (2 - ε, 2 + ε) and also some regularity results.Keywords: Partial differential equations; Problem solving; Variational techniques; Dirichlet problem; Regularization theory; Second order differential systems; Global optimization200810.1007/s10898-007-9272-82015-12-09