Consider the following premises. Patricia is a server. It is snowing if and only if Patricia is a server. Karen is sleeping. Can we infer the following from them? If we can, name the inference rule being used: It is not snowing.
 From the fact that it is snowing if and only if Patricia is a server we can infer that if Patricia were a server, then it is snowing via biconditional elimination. Finally, from the fact that if Patricia were a server, then it is snowing, and that Patricia is a server we can infer that it is snowing via modus ponens, which contradicts that It is not snowing. Therefore, the answer is no.