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: ~T_1(x). forall x: T_1(x) or U_2(x). exists x: U_2(x) <-> T_4(x).
forall x: U_2(x) can be inferred via the universal disjunctive syllogism rule. exists x: U_2(x) -> T_4(x) can be inferred via the existential biconditional elimination rule. exists x: T_4(x) -> U_2(x) can be inferred via the existential biconditional elimination rule.