Consider the following premises. There is at least one y_2 for which y_2 is a sailor. For all y_2, y_2 is an artist. For all y_2, if y_2 were a sailor, then y_2 is not an artist. Can we infer the following from them? There is at least one y_2 for which y_2 is sad.
 From the fact that for all y_2, if y_2 were a sailor, then y_2 is not an artist, and that for all y_2, y_2 is an artist we can infer that for all y_2, y_2 is not a sailor. From the fact that there is at least one y_2 for which y_2 is a sailor we can infer that there is at least one y_2 for which y_2 is a sailor or y_2 is sad. Finally, from the fact that there is at least one y_2 for which y_2 is a sailor or y_2 is sad, and that for all y_2, y_2 is not a sailor we can infer that there is at least one y_2 for which y_2 is sad. Therefore, the answer is yes. Notice, however, that the premises were contradictory, so we can infer anything from them.