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: S(x) -> U(x). exists x: U(x) -> S(x). forall x: U(x) <-> S(x).
exists x: U(x) <-> S(x) can be inferred via the existential biconditional introduction rule. exists x: S(x) <-> U(x) can be inferred via the existential biconditional introduction rule. forall x: U(x) -> S(x) can be inferred via the universal biconditional elimination rule. forall x: S(x) -> U(x) can be inferred via the universal biconditional elimination rule.