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, if z were a poet, then z is a writer. For all z, z is a writer. For all z, z is a poet if and only if z is a writer.
For all z, if z were a poet, then z is a writer can be inferred via the universal biconditional elimination rule. For all z, if z were a writer, then z is a poet can be inferred via the universal biconditional elimination rule.