Consider the following premises. There is at least one y_4 for which if y_4 were a poet, then y_4 is not a nurse. For all y_4, y_4 will play tennis if and only if y_4 is a nurse. For all y_4, y_4 will take a plane if and only if y_4 is a nurse. For all y_4, y_4 will take a plane or y_4 will play tennis. Can we infer the following from them? For all y_4, y_4 is a poet.
 From the fact that for all y_4, y_4 will play tennis if and only if y_4 is a nurse we can infer that for all y_4, if y_4 plays tennis, then y_4 is a nurse. From the fact that for all y_4, y_4 will take a plane if and only if y_4 is a nurse we can infer that for all y_4, if y_4 takes a plane, then y_4 is a nurse. From the fact that for all y_4, if y_4 takes a plane, then y_4 is a nurse, that for all y_4, if y_4 plays tennis, then y_4 is a nurse, and that for all y_4, y_4 will take a plane or y_4 will play tennis we can infer that for all y_4, y_4 is a nurse. Finally, from the fact that there is at least one y_4 for which if y_4 were a poet, then y_4 is not a nurse, and that for all y_4, y_4 is a nurse we can infer that there is at least one y_4 for which y_4 is not a poet, which contradicts that For all y_4, y_4 is a poet. Therefore, the answer is no.