Consider the following premises. t or P_13(a_10). forall x_13: P_13(x_13) <-> Q_13(x_13). t <-> Q_13(a_10). Can we infer Q_13(a_10) from them?
 From forall x_13: P_13(x_13) <-> Q_13(x_13) we can infer forall x_13: P_13(x_13) -> Q_13(x_13). From forall x_13: P_13(x_13) -> Q_13(x_13) we can infer P_13(a_10) -> Q_13(a_10). From t <-> Q_13(a_10) we can infer t -> Q_13(a_10). Finally, from t -> Q_13(a_10), P_13(a_10) -> Q_13(a_10), t or P_13(a_10) we can infer Q_13(a_10). Therefore, the answer is yes.