Consider the following premises. forall x_15: Q_19(x_15). forall x_19: P_19(x_19) <-> Q_19(x_19). Can we infer P_19(a_15) or p from them?
 From forall x_19: P_19(x_19) <-> Q_19(x_19) we can infer forall x_19: Q_19(x_19) -> P_19(x_19). From forall x_15: Q_19(x_15) we can infer Q_19(a_15). From forall x_19: Q_19(x_19) -> P_19(x_19) we can infer Q_19(a_15) -> P_19(a_15). From Q_19(a_15) -> P_19(a_15), Q_19(a_15) we can infer P_19(a_15). Finally, from P_19(a_15) we can infer P_19(a_15) or p. Therefore, the answer is yes.