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_6: R(x_6) -> W(x_6). forall x_6: T(x_6) -> W(x_6). forall x_6: W(x_6) -> T(x_6). forall x_6: R(x_6).
exists x_6: W(x_6) can be inferred via the existential modus ponens rule. exists x_6: R(x_6) -> T(x_6) can be inferred via the existential transitivity rule. forall x_6: T(x_6) <-> W(x_6) can be inferred via the universal biconditional introduction rule. forall x_6: W(x_6) <-> T(x_6) can be inferred via the universal biconditional introduction rule.