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_4 or ~p. p -> q_4. q_4 -> p.
p -> q_4 can be inferred via the rewriting rule. p <-> q_4 can be inferred via the biconditional introduction rule. q_4 <-> p can be inferred via the biconditional introduction rule.