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: Q_20(a_10). forall x_20: P(x_20) or ~Q_20(x_20).
exists x: Q_20(x) can be inferred via the existential generalization rule. forall x_20: Q_20(x_20) -> P(x_20) can be inferred via the universal rewriting rule.