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: P_2(x) or ~R_3(x). forall x: P(x) -> P_2(x). forall x: P_2(x) -> P(x). exists x: ~R(x) or P(x). forall x: R(x) or R_3(x).
exists x: R_3(x) or P(x) can be inferred via the existential resolution rule. forall x: R_3(x) -> P_2(x) can be inferred via the universal rewriting rule. forall x: P(x) <-> P_2(x) can be inferred via the universal biconditional introduction rule. forall x: P_2(x) <-> P(x) can be inferred via the universal biconditional introduction rule.