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 x_2, x_2 is a janitor and x_2 is a sailor.
For all x_2, x_2 is a janitor can be inferred via the universal simplification rule. For all x_2, x_2 is a sailor can be inferred via the universal simplification rule.