Consider the following premises. It is snowing if and only if Jessica is a doctor. It is snowing or Karen is not a server. If Jessica were a doctor, then Karen is a server. Can we infer the following from them? If we can, name the inference rule being used: The fact that it snows does not imply that Jessica is a doctor.
 From the fact that it is snowing or Karen is not a server we can infer that if Karen were a server, then it is snowing via rewriting. From the fact that if Jessica were a doctor, then Karen is a server, and that if Karen were a server, then it is snowing we can infer that if Jessica were a doctor, then it is snowing via transitivity. Finally, from the fact that it is snowing if and only if Jessica is a doctor we can infer that if it snows, then Jessica is a doctor via biconditional elimination, which contradicts that The fact that it snows does not imply that Jessica is a doctor. Therefore, the answer is no.