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: ~U(a_3) or p. forall x_6: P_6(x_6). forall x_6: P_6(x_6) -> U(x_6).
forall x_6: U(x_6) can be inferred via the universal modus ponens rule.