Consider the following premises. For all z_4, if z_4 plays squash, then z_4 is running. For all z_4, z_4 will play squash or z_4 will not go running. Can we infer the following from them? For all z_4, z_4 will go running if and only if z_4 will play squash.
 From the fact that for all z_4, z_4 will play squash or z_4 will not go running we can infer that for all z_4, if z_4 goes running, then z_4 is playing squash. Finally, from the fact that for all z_4, if z_4 goes running, then z_4 is playing squash, and that for all z_4, if z_4 plays squash, then z_4 is running we can infer that for all z_4, z_4 will go running if and only if z_4 will play squash. Therefore, the answer is yes.