Consider the following premises. If Linda climbs a mountain, then it is overcast. If Linda climbs a mountain, then it is overcast. It is snowing if and only if Linda is climbing a mountain. If it is overcast, 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 overcast if and only if Linda is climbing a mountain.
 From the fact that it is snowing if and only if Linda is climbing a mountain we can infer that if it snows, then Linda is climbing a mountain via biconditional elimination. From the fact that if it is overcast, then it is snowing, and that if it snows, then Linda is climbing a mountain we can infer that if it is overcast, then Linda is climbing a mountain via transitivity. Finally, from the fact that if it is overcast, then Linda is climbing a mountain, and that if Linda climbs a mountain, then it is overcast we can infer that it is overcast if and only if Linda is climbing a mountain via biconditional introduction, which contradicts that If is not true that it is overcast if and only if Linda is climbing a mountain. Therefore, the answer is no.