Consider the following premises. forall x_13: P_13(x_13) or Q_7(x_13). forall x_13: Q_7(x_13) -> S_2(x_13). exists x_13: P_13(x_13) <-> S_2(x_13). forall x_13: Q(x_13) -> ~S_2(x_13). Can we infer exists x_13: ~Q(x_13) from them?
 From exists x_13: P_13(x_13) <-> S_2(x_13) we can infer exists x_13: P_13(x_13) -> S_2(x_13). From exists x_13: P_13(x_13) -> S_2(x_13), forall x_13: Q_7(x_13) -> S_2(x_13), forall x_13: P_13(x_13) or Q_7(x_13) we can infer exists x_13: S_2(x_13). Finally, from forall x_13: Q(x_13) -> ~S_2(x_13), exists x_13: S_2(x_13) we can infer exists x_13: ~Q(x_13). Therefore, the answer is yes.