Consider the following premises. For all x, if x goes running, then x is sleeping. For all x, x is a taxi driver or x will not sleep. For all x, x will not climb a mountain. For all x, x is a taxi driver if and only if x will climb a mountain. There is at least one x for which if x were a taxi driver, then x is running. Can we infer the following from them? There is at least one x for which x will not go running.
 From the fact that for all x, x is a taxi driver if and only if x will climb a mountain, and that for all x, x will not climb a mountain we can infer that for all x, x is not a taxi driver. From the fact that for all x, x is a taxi driver or x will not sleep we can infer that for all x, if x sleeps, then x is a taxi driver. From the fact that for all x, if x goes running, then x is sleeping, and that for all x, if x sleeps, then x is a taxi driver we can infer that for all x, if x goes running, then x is a taxi driver. From the fact that there is at least one x for which if x were a taxi driver, then x is running, and that for all x, if x goes running, then x is a taxi driver we can infer that there is at least one x for which x is a taxi driver if and only if x will go running. Finally, from the fact that there is at least one x for which x is a taxi driver if and only if x will go running, and that for all x, x is not a taxi driver we can infer that there is at least one x for which x will not go running. Therefore, the answer is yes.