What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? p_9 <-> w_1. p_4 or p. ~w_1. p_4 <-> p_9.
p_9 -> w_1. p_4 -> p_9. w_1 -> p_9. p_9 -> p_4. ~p_9.