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_1: U(z_1) -> S(z_1). forall z_1: S(z_1) <-> W_1(z_1). forall z_1: ~T(z_1). forall z_1: W_1(z_1) -> T(z_1). exists z_1: S(z_1) -> U(z_1).
forall z_1: ~W_1(z_1) can be inferred via the universal modus tollens rule. exists z_1: S(z_1) <-> U(z_1) can be inferred via the existential biconditional introduction rule. exists z_1: U(z_1) <-> S(z_1) can be inferred via the existential biconditional introduction rule. forall z_1: S(z_1) -> W_1(z_1) can be inferred via the universal biconditional elimination rule. forall z_1: W_1(z_1) -> S(z_1) can be inferred via the universal biconditional elimination rule.