Consider the following premises. forall x_13: P(x_13) <-> S_13(x_13). q_1. ~P(a_13). Can we infer ~S_13(a_13) from them?
 From forall x_13: P(x_13) <-> S_13(x_13) we can infer P(a_13) <-> S_13(a_13). Finally, from P(a_13) <-> S_13(a_13), ~P(a_13) we can infer ~S_13(a_13). Therefore, the answer is yes.