Consider the following premises. forall y: ~S_2(y). ~u -> r_3. u <-> S_2(i_4). Can we infer r_3 from them?
 From forall y: ~S_2(y) we can infer ~S_2(i_4). From u <-> S_2(i_4), ~S_2(i_4) we can infer ~u. Finally, from ~u -> r_3, ~u we can infer r_3. Therefore, the answer is yes.