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 x: Q(x) -> S_2(x). forall x: T(x) -> S_2(x). exists x: Q(x) or T(x). forall x: S_2(x) -> Q(x). forall x: S_2(x) -> T(x).
forall x: Q(x) -> T(x) can be inferred via the universal transitivity rule. forall x: T(x) -> Q(x) can be inferred via the universal transitivity rule. exists x: S_2(x) can be inferred via the existential disjunction elimination rule. forall x: Q(x) <-> S_2(x) can be inferred via the universal biconditional introduction rule. forall x: T(x) <-> S_2(x) can be inferred via the universal biconditional introduction rule. forall x: S_2(x) <-> Q(x) can be inferred via the universal biconditional introduction rule. forall x: S_2(x) <-> T(x) can be inferred via the universal biconditional introduction rule.