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: R_3(x) <-> S_3(x). exists x: R_3(x) or ~S_3(x).
exists x: S_3(x) -> R_3(x) can be inferred via the existential rewriting rule. forall x: R_3(x) -> S_3(x) can be inferred via the universal biconditional elimination rule. forall x: S_3(x) -> R_3(x) can be inferred via the universal biconditional elimination rule.