2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/41391We review our works on the sequential fourth generation model and focus on the constriants of $4\times 4$ quark mixing matrix elements. We investigate the quark mixing matrix elements from the rare $K,B$ meson decays. We talk about the $ hierarchy$ of the $4\times 4$ matrix and the existence of fourth generation.14 pages, 4 figures, submitted to PRDHigh Energy Physics - Phenomenologytext