Consider the following premises. Karen is a server if and only if Patricia is a lawyer. Susan is playing tennis and Thomas is a bartender. Karen is not a server. Can we infer the following from them? If we can, name the inference rule being used: Patricia is a lawyer.
 From the fact that Susan is playing tennis and Thomas is a bartender we can infer that Susan is playing tennis via simplification. Finally, from the fact that Karen is a server if and only if Patricia is a lawyer, and that Karen is not a server we can infer that Patricia is not a lawyer via biconditional elimination, which contradicts that Patricia is a lawyer. Therefore, the answer is no.