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_4, x_4 is not an artist or x_4 will go running. For all x_4, if x_4 were rich, then x_4 is taking a plane. There is at least one x_4 for which x_4 will not take a plane. For all x_4, x_4 is an artist or x_4 is rich.
There is at least one x_4 for which x_4 is not rich can be inferred via the existential modus tollens rule. For all x_4, x_4 is rich or x_4 will go running can be inferred via the universal resolution rule.