Consider the following premises. forall x_3: P_3(x_3) -> Q_3(x_3). forall x_3: Q_3(x_3) -> P_3(x_3). Can we infer P_3(g) -> Q_3(g) from them?
 From forall x_3: P_3(x_3) -> Q_3(x_3), forall x_3: Q_3(x_3) -> P_3(x_3) we can infer forall x_3: P_3(x_3) <-> Q_3(x_3). From forall x_3: P_3(x_3) <-> Q_3(x_3) we can infer P_3(g) <-> Q_3(g). Finally, from P_3(g) <-> Q_3(g) we can infer P_3(g) -> Q_3(g). Therefore, the answer is yes.