Consider the following premises. For all x_7, x_7 is a police officer if and only if x_7 will sleep. Thomas is excited if and only if it is windy. It is not windy. If Patricia sleeps, then Thomas is excited. Can we infer the following from them? If we can, name the inference rule being used: Patricia is a police officer.
 From the fact that Thomas is excited if and only if it is windy, and that it is not windy we can infer that Thomas is not excited via biconditional elimination. From the fact that for all x_7, x_7 is a police officer if and only if x_7 will sleep we can infer that Patricia is a police officer if and only if Patricia is sleeping via universal instantiation. From the fact that if Patricia sleeps, then Thomas is excited, and that Thomas is not excited we can infer that Patricia is not sleeping via modus tollens. Finally, from the fact that Patricia is a police officer if and only if Patricia is sleeping, and that Patricia is not sleeping we can infer that Patricia is not a police officer via biconditional elimination, which contradicts that Patricia is a police officer. Therefore, the answer is no.