Consider the following premises. u. S(b_2) or t_3. forall y: ~S(y). Can we infer ~t_3 from them?
 From forall y: ~S(y) we can infer ~S(b_2). Finally, from S(b_2) or t_3, ~S(b_2) we can infer t_3, which contradicts ~t_3. Therefore, the answer is no.