Ayouba Kassoum LEM-CNRS (UMR 9222), IESEG School of Management   IESEG School of Management 3, rue de la Digue LIlle, Nord 59000 France   a.kassoum@ieseg.fr             JEL Areas: Q0 : Agricultural and Natural Resource Economics; Environmental and Ecological Economics: General C6 : Mathematical Methods and Programming: General