Constraints of mixing matrix elements in the sequential fourthgeneration   model
  We 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. 
W.J. Huo (IHEP, CAS, China)