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: exists x: ~T_4(x). forall x: P(x) <-> T_4(x). forall x: P(x) -> S_1(x). forall x: S_1(x) -> P(x).
forall x: P(x) <-> S_1(x) can be inferred via the universal biconditional introduction rule. forall x: S_1(x) <-> P(x) can be inferred via the universal biconditional introduction rule. forall x: P(x) -> T_4(x) can be inferred via the universal biconditional elimination rule. forall x: T_4(x) -> P(x) can be inferred via the universal biconditional elimination rule. exists x: ~P(x) can be inferred via the existential biconditional elimination rule.