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 -> p_13. w_4 -> p_13. p_13 -> p. ~p. p_13 <-> w_4.
~p_13 can be inferred via the modus tollens rule. w_4 -> p can be inferred via the transitivity rule. p <-> p_13 can be inferred via the biconditional introduction rule. p_13 <-> p can be inferred via the biconditional introduction rule. p_13 -> w_4 can be inferred via the biconditional elimination rule. w_4 -> p_13 can be inferred via the biconditional elimination rule.