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 mechanic if and only if z is a carpenter. For all x_8, x_8 is a mechanic.
For all z, if z were a mechanic, then z is a carpenter can be inferred via the universal biconditional elimination rule. For all z, if z were a carpenter, then z is a mechanic can be inferred via the universal biconditional elimination rule.