What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? p_18 <-> r_3. ~p_18. forall z: P_1(z) or P(z). forall z: ~P_1(z).
p_18 -> r_3. r_3 -> p_18. ~r_3. forall z: P(z).