2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/214013This paper has been withdrawn by the authors, because it has been made obsolete by the detailed expositions in our papers in arXiv:0812.4885 (the mathematics part) and arXiv:0812.4737 (the economics part).This paper has been withdrawn by the authorsGeneral FinancePhysics and Societytext