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: John is a police officer if and only if Michael is a nurse. Michael is a nurse.
If John were a police officer, then Michael is a nurse can be inferred via the biconditional elimination rule. If Michael were a nurse, then John is a police officer can be inferred via the biconditional elimination rule.