Consider the following premises. Linda is rich if and only if it is snowing. Linda is not a doctor. For all y_2, if y_2 were rich, then y_2 is a doctor. Can we infer the following from them? If we can, name the inference rule being used: It is snowing.
 From the fact that for all y_2, if y_2 were rich, then y_2 is a doctor we can infer that if Linda were rich, then Linda is a doctor via universal instantiation. From the fact that Linda is rich if and only if it is snowing we can infer that if it snows, then Linda is rich via biconditional elimination. From the fact that if Linda were rich, then Linda is a doctor, and that Linda is not a doctor we can infer that Linda is not rich via modus tollens. Finally, from the fact that if it snows, then Linda is rich, and that Linda is not rich we can infer that it is not snowing via modus tollens, which contradicts that It is snowing. Therefore, the answer is no.