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_4: S(x_4). forall x_4: P_2(x_4) -> T_4(x_4). forall x_4: P_3(x_4) -> T_1(x_4). forall x_4: S(x_4) -> P_3(x_4). forall x_4: P_2(x_4) <-> T_1(x_4).
exists x_4: P_3(x_4) can be inferred via the existential modus ponens rule. forall x_4: S(x_4) -> T_1(x_4) can be inferred via the universal transitivity rule. forall x_4: P_2(x_4) -> T_1(x_4) can be inferred via the universal biconditional elimination rule. forall x_4: T_1(x_4) -> P_2(x_4) can be inferred via the universal biconditional elimination rule.