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: For all y_3, if y_3 were a janitor, then y_3 is taking a plane. For all y_3, if y_3 were a taxi driver, then y_3 is a janitor. For all y_3, y_3 is sad or y_3 will not take a plane.
For all y_3, if y_3 were a taxi driver, then y_3 is taking a plane can be inferred via the universal transitivity rule. For all y_3, if y_3 takes a plane, then y_3 is sad can be inferred via the universal rewriting rule.