Consider the following premises. ~Q_17(j). forall x_17: P_17(x_17) <-> Q_17(x_17). Can we infer ~P_17(j) or s_2 from them?
 From forall x_17: P_17(x_17) <-> Q_17(x_17) we can infer forall x_17: P_17(x_17) -> Q_17(x_17). From forall x_17: P_17(x_17) -> Q_17(x_17) we can infer P_17(j) -> Q_17(j). From P_17(j) -> Q_17(j), ~Q_17(j) we can infer ~P_17(j). Finally, from ~P_17(j) we can infer ~P_17(j) or s_2. Therefore, the answer is yes.