Consider the following premises. If it rains, then it is snowing. It is snowing if and only if it is raining. If it rains, then it is snowing. Can we infer the following from them? If we can, name the inference rule being used: If is not true that it is raining if and only if it is snowing.
 From the fact that it is snowing if and only if it is raining we can infer that if it snows, then it is raining via biconditional elimination. Finally, from the fact that if it rains, then it is snowing, and that if it snows, then it is raining we can infer that it is raining if and only if it is snowing via biconditional introduction, which contradicts that If is not true that it is raining if and only if it is snowing. Therefore, the answer is no.