Consider the following premises. Linda is an artist or it is not snowing. If Linda were an artist, then it is snowing. Linda is an artist if and only if it is snowing. Can we infer the following from them? If we can, name the inference rule being used: It is snowing if and only if Linda is an artist.
 From the fact that Linda is an artist or it is not snowing we can infer that if it snows, then Linda is an artist via rewriting. Finally, from the fact that if it snows, then Linda is an artist, and that if Linda were an artist, then it is snowing we can infer that it is snowing if and only if Linda is an artist via biconditional introduction. Therefore, the answer is yes.