Consider the following premises. T_4(a) and s. forall y: ~T_4(y). Can we infer u from them?
 From forall y: ~T_4(y) we can infer ~T_4(a). From T_4(a) and s we can infer T_4(a). From T_4(a) we can infer T_4(a) or u. Finally, from T_4(a) or u, ~T_4(a) we can infer u. Therefore, the answer is yes. Notice, however, that the premises were contradictory, so we can infer anything from them.