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_2: R_2(x_2) <-> S_2(x_2). ~S_2(d).
forall x_2: R_2(x_2) -> S_2(x_2) can be inferred via the universal biconditional elimination rule. forall x_2: S_2(x_2) -> R_2(x_2) can be inferred via the universal biconditional elimination rule.