Consider the following premises. If Susan reads a book, then Richard is bored. Richard is not a sailor. For all x_1, x_1 is a sailor if and only if x_1 is bored. Can we infer the following from them? If we can, name the inference rule being used: Susan is reading a book.
 From the fact that for all x_1, x_1 is a sailor if and only if x_1 is bored we can infer that Richard is a sailor if and only if Richard is bored via universal instantiation. From the fact that Richard is a sailor if and only if Richard is bored, and that Richard is not a sailor we can infer that Richard is not bored via biconditional elimination. Finally, from the fact that if Susan reads a book, then Richard is bored, and that Richard is not bored we can infer that Susan is not reading a book via modus tollens, which contradicts that Susan is reading a book. Therefore, the answer is no.