Consider the following premises. w <-> q_19. forall x_7: R_7(x_7) <-> S_7(x_7). p -> q_19. S_7(a_7) <-> p. ~w. Can we infer R_7(a_7) from them? If possible, name the inference rules being used at each step.
 From w <-> q_19, ~w we can infer ~q_19 via biconditional elimination. From p -> q_19, ~q_19 we can infer ~p via modus tollens. From forall x_7: R_7(x_7) <-> S_7(x_7) we can infer R_7(a_7) <-> S_7(a_7) via universal instantiation. From S_7(a_7) <-> p, ~p we can infer ~S_7(a_7) via biconditional elimination. Finally, from R_7(a_7) <-> S_7(a_7), ~S_7(a_7) we can infer ~R_7(a_7) via biconditional elimination, which contradicts R_7(a_7). Therefore, the answer is no.