First Author:   Siddhartha Mitra Department of Economics, Jadavpur University mitsid@yahoo.com   Department of Economics, Jadavpur University Kolkata, 700032, India       Second Author: Nilangshu Acharya Department of Mathematics, P.R. Thakur Govt. College nilangshu.math@gmail.com   Thakurnagar, 743287, India       Third Author: Samir Kumar Bhandari Department of Math., Bajkul Milani Mahavidyalaya skbhit@yahoo.co.in   Department of Math, B.M. Mahavidyalaya, P.O-, Kismat Bajkul, Purba Medinipur, India