Consider the following premises. For all x_13, x_13 is a scientist if and only if x_13 will play a game. There is at least one x_13 for which x_13 will play a game. Can we infer the following from them? There is at least one x_13 for which x_13 is a scientist or x_13 will take a plane.
 From the fact that for all x_13, x_13 is a scientist if and only if x_13 will play a game we can infer that for all x_13, if x_13 plays a game, then x_13 is a scientist. From the fact that for all x_13, if x_13 plays a game, then x_13 is a scientist, and that there is at least one x_13 for which x_13 will play a game we can infer that there is at least one x_13 for which x_13 is a scientist. Finally, from the fact that there is at least one x_13 for which x_13 is a scientist we can infer that there is at least one x_13 for which x_13 is a scientist or x_13 will take a plane. Therefore, the answer is yes.