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_18: Q_18(x_18) -> R_3(x_18). forall x_18: S(x_18) or Q_18(x_18). exists x_18: S(x_18) -> R_3(x_18). forall x_18: W_1(x_18).
exists x_18: R_3(x_18) can be inferred via the existential disjunction elimination rule.