2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/112513This Ph.D. thesis collects results obtained investigating two different aspects of modern unifying theories. In the first part I summarized results achieved investigating simplicial aspects of string dualities. Exploiting Boundary Conformal Field Theory techniques, I investigated the coupling between random Regge triangulations and open string theory, discussing its implications in gauge/gravity correspondence. The second part reports results obtained in the paper hep-th/0309237, devoted to look for cosmological backgrounds of superstring theories.199 pages, Ph.D. Thesis (Advisor: Mauro Carfora)High Energy Physics - Theorytext