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 z, z is a politician if and only if z is an artist. There is at least one z for which if z were a politician, then z is fast. For all z, z is an artist if and only if z is fast.
For all z, if z were a politician, 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 fast can be inferred via the universal biconditional elimination rule. For all z, if z were an artist, then z is a politician can be inferred via the universal biconditional elimination rule. For all z, if z were fast, then z is an artist can be inferred via the universal biconditional elimination rule.