Consider the following premises. ~U_1(a) or u. forall x_7: ~P_7(x_7) or U_1(x_7). forall x_7: P_7(x_7) or Q_7(x_7). forall x_7: ~Q_7(x_7) or R_5(x_7). Can we infer R_5(a) or u from them?
 From forall x_7: P_7(x_7) or Q_7(x_7), forall x_7: ~P_7(x_7) or U_1(x_7) we can infer forall x_7: Q_7(x_7) or U_1(x_7). From forall x_7: Q_7(x_7) or U_1(x_7), forall x_7: ~Q_7(x_7) or R_5(x_7) we can infer forall x_7: U_1(x_7) or R_5(x_7). From forall x_7: U_1(x_7) or R_5(x_7) we can infer U_1(a) or R_5(a). Finally, from U_1(a) or R_5(a), ~U_1(a) or u we can infer R_5(a) or u. Therefore, the answer is yes.