Consider the following premises. For all x_13, x_13 will not read a book. There is at least one x_13 for which if x_13 goes running, then x_13 is playing squash. For all x_13, x_13 will play squash if and only if x_13 will go running. For all x_13, x_13 will read a book or x_13 will not go running. Can we infer the following from them? There is at least one x_13 for which x_13 will not play squash.
 From the fact that for all x_13, x_13 will play squash if and only if x_13 will go running we can infer that for all x_13, if x_13 plays squash, then x_13 is running. From the fact that for all x_13, x_13 will read a book or x_13 will not go running we can infer that for all x_13, if x_13 goes running, then x_13 is reading a book. From the fact that there is at least one x_13 for which if x_13 goes running, then x_13 is playing squash, and that for all x_13, if x_13 plays squash, then x_13 is running we can infer that there is at least one x_13 for which x_13 will go running if and only if x_13 will play squash. From the fact that for all x_13, if x_13 goes running, then x_13 is reading a book, and that for all x_13, x_13 will not read a book we can infer that for all x_13, x_13 will not go running. Finally, from the fact that there is at least one x_13 for which x_13 will go running if and only if x_13 will play squash, and that for all x_13, x_13 will not go running we can infer that there is at least one x_13 for which x_13 will not play squash. Therefore, the answer is yes.