 Since 1985 he is Professor of Analysis in Florence.He was there Dean of the Faculty of Mathematics, Physics and Natural Sciences, Director of the Department of Mathematics "Ulisse Dini" and Coordinator of the graduate program in mathematics (PhD Doctoral Studies).He was a visiting scientist, among others, the Collège de France in Paris, Bonn and Leipzig (University and Max Planck Institute), University of California at Berkeley, EPFL at Lausanne, Mathematical Institute of the University of Oxford, Carnegie-Mellon University in Pittsburgh, Lisbon, Instituto Argentino de Matematica in Buenos Aires, Russian Academy of Sciences Akademgorodok in Novosibirsk, the Institute for Advanced Study in Princeton, the University of Texas at Austin, University of Zurich, University of Cologne in Köln, University of Erlangen-Nuremberg, Hokkaido University in Tokyo, Academia Sinica in Taipei-Taiwan, the Australian National University and the Mittag-Leffler Institute in Sweden.