Department of Mathematics and Statistics, University of Strathclyde, 16 Richmond Street, Glasgow G1 1XQ, UK; LJAD, CNRS, University Côte d’Azur, 28 Avenue de Valrose, 06108 Nice CEDEX 2, France
Prof. Dr. Victorita Dolean
Department of Mathematics and Statistics, University of Strathclyde, 16 Richmond Street, Glasgow G1 1XQ, UK; LJAD, CNRS, University Côte d’Azur, 28 Avenue de Valrose, 06108 Nice CEDEX 2, France