Consider the following premises. If Robert works, then Robert is playing a game. Robert is not working. For all z, z will play a game if and only if z will work. Can we infer the following from them? Robert is not playing a game.
 From the fact that for all z, z will play a game if and only if z will work we can infer that for all z, if z plays a game, then z is working. From the fact that for all z, if z plays a game, then z is working we can infer that if Robert plays a game, then Robert is working. From the fact that if Robert plays a game, then Robert is working, and that if Robert works, then Robert is playing a game we can infer that Robert is playing a game if and only if Robert is working. Finally, from the fact that Robert is playing a game if and only if Robert is working, and that Robert is not working we can infer that Robert is not playing a game. Therefore, the answer is yes.