Consider a game, G, with 2 players, where player 1 chooses between U and D, player 2 chooses between L and R. Suppose (U, R) is a Nash equilibrium. Now consider another game G*, which is like G in every way except that player 1's payoffs are now different. There is a number b > 0, such that if from an outcome in G player 1 got a payoff of , then from the same outcome in game G* she gets a payoff of b, where b > 0.