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: p_2 or p_4. p_2 -> q_4. p <-> q_4. ~p.
p -> q_4 can be inferred via the biconditional elimination rule. q_4 -> p can be inferred via the biconditional elimination rule. ~q_4 can be inferred via the biconditional elimination rule.