Consider the following premises. For all x_12, x_12 will play squash if and only if x_12 is a server. There is at least one x_12 for which if x_12 were a server, then x_12 is excited. For all x_12, x_12 is excited if and only if x_12 will play squash. Can we infer the following from them? For all x_12, if is not true that x_12 will play squash if and only if x_12 is excited.
That contradicts the premises. Therefore the answer is no.