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 an office clerk or z is a janitor. For all z, z is an artist if and only if z is an office clerk. For all z, z is a janitor if and only if z is an artist.
For all z, if z were an artist, then z is an office clerk can be inferred via the universal biconditional elimination rule. For all z, if z were a janitor, then z is an artist can be inferred via the universal biconditional elimination rule. For all z, if z were an office clerk, then z is an artist can be inferred via the universal biconditional elimination rule. For all z, if z were an artist, then z is a janitor can be inferred via the universal biconditional elimination rule.