Consider the following premises. If David plays squash, then William is a writer. David is playing squash or William is not a writer. William is not a writer. Can we infer the following from them? If we can, name the inference rule being used: David is playing squash.
 From the fact that David is playing squash or William is not a writer we can infer that if William were a writer, then David is playing squash via rewriting. From the fact that if William were a writer, then David is playing squash, and that if David plays squash, then William is a writer we can infer that William is a writer if and only if David is playing squash via biconditional introduction. Finally, from the fact that William is a writer if and only if David is playing squash, and that William is not a writer we can infer that David is not playing squash via biconditional elimination, which contradicts that David is playing squash. Therefore, the answer is no.