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 if z were poor, then z is a musician. For all z, z is not fast. For all z, if z were a musician, then z is fast. For all z, if z were fast, then z is a musician.
For all z, z is not a musician can be inferred via the universal modus tollens rule. There is at least one z for which if z were poor, then z is fast can be inferred via the existential transitivity rule. For all z, z is a musician if and only if z is fast can be inferred via the universal biconditional introduction rule. For all z, z is fast if and only if z is a musician can be inferred via the universal biconditional introduction rule.