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: Q_12(x_12) -> R_6(x_12). forall x_12: S(x_12) <-> Q_12(x_12). ~R_6(a_5).
forall x_12: S(x_12) -> Q_12(x_12) can be inferred via the universal biconditional elimination rule. forall x_12: Q_12(x_12) -> S(x_12) can be inferred via the universal biconditional elimination rule.