1. Department of Mathematics, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India. E-mail: hutri@math.iitb.ac.in
2. Université Paris-Dauphine, PSL University, CNRS, UMR 7534, CEREMADE, 75016 Paris, France. E-mail: mula@ceremade.dauphine.fr
3. Università degli Studi di Pavia, Dipartimento di Matematica, I-27100 Pavia, Italy. E-mail: francesco.salvarani@unipv.it