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: There is at least one z for which z is rich if and only if z is an artist. For all z, z is an artist or z is not rich.
For all z, if z were rich, then z is an artist can be inferred via the universal rewriting rule. There is at least one z for which if z were rich, then z is an artist can be inferred via the existential biconditional elimination rule. There is at least one z for which if z were an artist, then z is rich can be inferred via the existential biconditional elimination rule.