Consider the following premises. For all x_18, x_18 will play a game if and only if x_18 is a politician. William is an electrician. It is not cold. Charles is a politician if and only if it is cold. Can we infer the following from them? Charles is playing a game.
 From the fact that for all x_18, x_18 will play a game if and only if x_18 is a politician we can infer that Charles is playing a game if and only if Charles is a politician. From the fact that Charles is a politician if and only if it is cold, and that it is not cold we can infer that Charles is not a politician. Finally, from the fact that Charles is playing a game if and only if Charles is a politician, and that Charles is not a politician we can infer that Charles is not playing a game, which contradicts that Charles is playing a game. Therefore, the answer is no.