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: ~w_4. p_8 <-> p. w_4 <-> p.
p_8 -> p can be inferred via the biconditional elimination rule. w_4 -> p can be inferred via the biconditional elimination rule. p -> p_8 can be inferred via the biconditional elimination rule. p -> w_4 can be inferred via the biconditional elimination rule. ~p can be inferred via the biconditional elimination rule.