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_2(x). exists x: S(x) or P(x). forall x: S_2(x) <-> S(x).
forall x: S_2(x) -> S(x) can be inferred via the universal biconditional elimination rule. forall x: S(x) -> S_2(x) can be inferred via the universal biconditional elimination rule. forall x: ~S(x) can be inferred via the universal biconditional elimination rule.