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→Examples of differences between Nash equilibria and ESSes 纳什均衡与进化均衡策略之间差异的示例
In most simple games, the ESSes and Nash equilibria coincide perfectly. For instance, in the prisoner's dilemma there is only one Nash equilibrium, and its strategy (Defect) is also an ESS.
In most simple games, the ESSes and Nash equilibria coincide perfectly. For instance, in the prisoner's dilemma there is only one Nash equilibrium, and its strategy (Defect) is also an ESS.
在大多数简单的游戏中，进化均衡策略和纳什均衡完全重合。例如，在游戏'''<font color="#ff8000"> 《囚徒困境Prisoner's Dilemma》</font>'''中，只有一个纳什均衡，其策略（叛变）也是一种进化均衡策略。
Some games may have Nash equilibria that are not ESSes. For example, in harm thy neighbor (whose payoff matrix is shown here) both (A, A) and (B, B) are Nash equilibria, since players cannot do better by switching away from either. However, only B is an ESS (and a strong Nash). A is not an ESS, so B can neutrally invade a population of A strategists and predominate, because B scores higher against B than A does against B. This dynamic is captured by Maynard Smith's second condition, since E(A, A) = E(B, A), but it is not the case that E(A,B) > E(B,B).
Some games may have Nash equilibria that are not ESSes. For example, in harm thy neighbor (whose payoff matrix is shown here) both (A, A) and (B, B) are Nash equilibria, since players cannot do better by switching away from either. However, only B is an ESS (and a strong Nash). A is not an ESS, so B can neutrally invade a population of A strategists and predominate, because B scores higher against B than A does against B. This dynamic is captured by Maynard Smith's second condition, since E(A, A) = E(B, A), but it is not the case that E(A,B) > E(B,B).
还有一些游戏可能具有非进化均衡策略的纳什均衡。例如，在游戏'''<font color="#ff8000"> 《以邻为壑Harm thy neighbor》</font>'''中（此处显示为回报矩阵），（A，A）和（B，B）都是纳什均衡，因为玩家无法通过选择放弃任一个来做得更好。但是，只有B是进化均衡策略（也是强纳什）。A不是进化均衡策略，因此B可以中立地入侵A策略的群体并占据优势地位，因为B对B的得分要比A对B的得分高。由于E（A，A）= E（B，A），因此可以通过梅纳德·史密斯的第二个条件来捕获此动态，但是E（A，B）> E（B，B）并非如此。
Nash equilibria with equally scoring alternatives can be ESSes. For example, in the game Harm everyone, C is an ESS because it satisfies Maynard Smith's second condition. D strategists may temporarily invade a population of C strategists by scoring equally well against C, but they pay a price when they begin to play against each other; C scores better against D than does D. So here although E(C, C) = E(D, C), it is also the case that E(C,D) > E(D,D). As a result, C is an ESS.
Nash equilibria with equally scoring alternatives can be ESSes. For example, in the game Harm everyone, C is an ESS because it satisfies Maynard Smith's second condition. D strategists may temporarily invade a population of C strategists by scoring equally well against C, but they pay a price when they begin to play against each other; C scores better against D than does D. So here although E(C, C) = E(D, C), it is also the case that E(C,D) > E(D,D). As a result, C is an ESS.
纳什均衡以及同等评分的策略都可以是进化均衡策略。例如，在游戏'''<font color="#ff8000"> 《伤害大家Harm everyone》</font>'''中，C是进化均衡策略，因为它满足了梅纳德·史密斯的第二条件。D策略可以暂时入侵C策略群体，因为D策略可以获得和C策略一样的评分。但是当他们开始互相对抗时，他们会付出一定的代价；C对D的得分比D对D的得分高。因此，尽管E（C，C）=E（D，C），但E（C，D）> E（D，D）。因此，最后C是最终进化均衡策略。
Even if a game has pure strategy Nash equilibria, it might be that none of those pure strategies are ESS. Consider the Game of chicken. There are two pure strategy Nash equilibria in this game (Swerve, Stay) and (Stay, Swerve). However, in the absence of an uncorrelated asymmetry, neither Swerve nor Stay are ESSes. There is a third Nash equilibrium, a mixed strategy which is an ESS for this game (see Hawk-dove game and Best response for explanation).
Even if a game has pure strategy Nash equilibria, it might be that none of those pure strategies are ESS. Consider the Game of chicken. There are two pure strategy Nash equilibria in this game (Swerve, Stay) and (Stay, Swerve). However, in the absence of an uncorrelated asymmetry, neither Swerve nor Stay are ESSes. There is a third Nash equilibrium, a mixed strategy which is an ESS for this game (see Hawk-dove game and Best response for explanation).
还有一些游戏即使具有纯粹的纳什均衡策略，但可能它们都不是进化均衡策略。比如游戏'''<font color="#ff8000"> 《小鸡博弈The Game of Chicken》</font>''',该游戏中有两种纯粹的纳什均衡策略（转身离开Swerve，留下Stay）和（留下Stay，转身离开Swerve）。但是，在无关联不对称Uncorrelated Asymmetry缺失的情况下，Swerve和Stay都不是进化均衡策略。此时存在第三种纳什均衡，它属于混合策略并且是该游戏的进化均衡策略（详情请参见'''<font color="#ff8000"> 《鹰鸽博弈Hawk-dove》</font>'''游戏和'''<font color="#ff8000"> 《最佳响应Best Response》</font>'''以获得解释）。