Consider the following premises. For all x_12, x_12 is not a doctor. There is at least one x_12 for which x_12 will play squash if and only if x_12 is an artist. For all x_12, x_12 will play squash if and only if x_12 is a doctor. For all x_12, x_12 is an artist if and only if x_12 will go running. Can we infer the following from them? There is at least one x_12 for which x_12 will not go running.
 From the fact that for all x_12, x_12 will play squash if and only if x_12 is a doctor, and that for all x_12, x_12 is not a doctor we can infer that for all x_12, x_12 will not play squash. From the fact that there is at least one x_12 for which x_12 will play squash if and only if x_12 is an artist, and that for all x_12, x_12 will not play squash we can infer that there is at least one x_12 for which x_12 is not an artist. Finally, from the fact that for all x_12, x_12 is an artist if and only if x_12 will go running, and that there is at least one x_12 for which x_12 is not an artist we can infer that there is at least one x_12 for which x_12 will not go running. Therefore, the answer is yes.