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: forall z: ~P_1(z). p_18 <-> r_3. forall z: P_1(z) or P(z). ~p_18.
p_18 -> r_3 can be inferred via the biconditional elimination rule. r_3 -> p_18 can be inferred via the biconditional elimination rule. ~r_3 can be inferred via the biconditional elimination rule. forall z: P(z) can be inferred via the universal disjunctive syllogism rule.