Gisèle Ruiz Goldstein is Professor, Department of Mathematical Sciences, University of Memphis, Tennessee. She is the author of more than 40 journal articles and coeditor of four books. Her research interests include partial differential equations, semigroups of operators, and mathematical physics. She received the B.S. (1980) and Ph.D. (1986) degrees in mathematics from Tulane University, New Orleans, Louisiana. Rainer Nagel is Professor of Mathematics, University of Tübingen, Germany. He is the author of nearly 100 research papers and two books and is editor-in-chief of the Journal of Evolution Equations. He also serves on the editorial boards of Semigroup Forum, Positivity, and several other journals. Professor Nagel is a member of Deutsche Maathematiker Vereinigung, the Unione Matematica Italiana, the American Mathematical Society, and the Society for Industrial and Applied Mathematics and serves as coordinator of the TULKA research group. Professor Nagel received the Ph.D. degree (1969) and Habilitation (1973) from the University of Tübingen, Germany. Silvia Romanelli is Associate Professor, Department of Mathematics, University of Bari, Italy. The author or coauthor of nearly 50 papers, her research interests include problems of existence and regularity of semigroups generated by differential operators and their applications. The coordinator of research and mobility programs, she is a member of the Unione Matematica Italiana and the European Mathematical Society. She received the degree (1973) in mathematics from the University of Bari, Italy.
