Affiliation: | (1) Dipartimento SEMEQ, Universitá degli Studi del Piemonte Orientale, Via Perrone 18, 28100 Novara, Italy;(2) Present address: Italy and Associate Fellow, Financial Options Research Centre, Warwick Business School, UK;(3) Department of Mathematics, University of Manchester, Oxford Road, M13 9PL Manchester, UK;(4) Dipartimento di Matematica, Politecnico di Milano, IV Facoltá di Ingegneria, Via La Masa 34, 20158 Milano, Italy |