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: Q_2(x) <-> S(x). forall x: U_1(x) or ~Q_2(x).
forall x: Q_2(x) -> U_1(x) can be inferred via the universal rewriting rule. exists x: Q_2(x) -> S(x) can be inferred via the existential biconditional elimination rule. exists x: S(x) -> Q_2(x) can be inferred via the existential biconditional elimination rule.