Consider the following premises. There is at least one z_1 for which if z_1 goes running, then z_1 is curious. For all z_1, z_1 will not work. For all z_1, z_1 will go running if and only if z_1 will work. For all z_1, if z_1 were curious, then z_1 is running. Can we infer the following from them? If we can, name the inference rule being used: For all z_1, z_1 is curious.
 From the fact that for all z_1, z_1 will go running if and only if z_1 will work, and that for all z_1, z_1 will not work we can infer that for all z_1, z_1 will not go running via universal biconditional elimination. From the fact that there is at least one z_1 for which if z_1 goes running, then z_1 is curious, and that for all z_1, if z_1 were curious, then z_1 is running we can infer that there is at least one z_1 for which z_1 will go running if and only if z_1 is curious via existential biconditional introduction. Finally, from the fact that there is at least one z_1 for which z_1 will go running if and only if z_1 is curious, and that for all z_1, z_1 will not go running we can infer that there is at least one z_1 for which z_1 is not curious via existential biconditional elimination, which contradicts that For all z_1, z_1 is curious. Therefore, the answer is no.