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_4. p_4 <-> p.
p_4 -> p can be inferred via the biconditional elimination rule. p -> p_4 can be inferred via the biconditional elimination rule. ~p can be inferred via the biconditional elimination rule.