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: W_1(z) <-> W_2(z). exists z: S_2(z). forall z: S_2(z) -> W_2(z).
exists z: W_2(z) can be inferred via the existential modus ponens rule. forall z: W_1(z) -> W_2(z) can be inferred via the universal biconditional elimination rule. forall z: W_2(z) -> W_1(z) can be inferred via the universal biconditional elimination rule.