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_13: P_13(x_13) or Q_13(x_13). forall x_13: P_4(x_13) and Q_3(x_13). forall x_13: Q_13(x_13) -> S_1(x_13). forall x_13: P_13(x_13) -> S_1(x_13).
forall x_13: P_4(x_13) can be inferred via the universal simplification rule. forall x_13: Q_3(x_13) can be inferred via the universal simplification rule. exists x_13: S_1(x_13) can be inferred via the existential disjunction elimination rule.