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: David is a doctor if and only if it is snowing. If it snows, then Michael is rich. It is not cloudy. Michael is rich if and only if it is cloudy.
If David were a doctor, then it is snowing can be inferred via the biconditional elimination rule. If Michael were rich, then it is cloudy can be inferred via the biconditional elimination rule. If it snows, then David is a doctor can be inferred via the biconditional elimination rule. If it is cloudy, then Michael is rich can be inferred via the biconditional elimination rule. Michael is not rich can be inferred via the biconditional elimination rule.