What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: forall x_12: R_12(x_12) <-> S_12(x_12). ~q_3. q_3 <-> q_15. q_15 or ~R_12(a_12).
R_12(a_12) -> q_15 can be inferred via the rewriting rule. q_3 -> q_15 can be inferred via the biconditional elimination rule. q_15 -> q_3 can be inferred via the biconditional elimination rule. ~q_15 can be inferred via the biconditional elimination rule. forall x_12: R_12(x_12) -> S_12(x_12) can be inferred via the universal biconditional elimination rule. forall x_12: S_12(x_12) -> R_12(x_12) can be inferred via the universal biconditional elimination rule.