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: q <-> S(a_4). forall x_1: S(x_1).
q -> S(a_4) can be inferred via the biconditional elimination rule. S(a_4) -> q can be inferred via the biconditional elimination rule.