来自《耶鲁大学开放课程：博弈论 第11集 第11集》

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  Strategy B, okay that's correct. Your name is?
  策略B 正确 请问你叫什么
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  Greg.
  格雷格
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  So Greg is saying strategy B might invade here,
  格雷格说策略B可能会入侵
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  let's have a look, let's see what happens.
  我们来看看是不是这样的
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  So suppose there's an invasion of B,
  假如采取策略B的突变个体入侵了
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  so again the T.A.'s are playing B, everyone else is playing C,
  这次还是一样 助教们选B而其他人选C
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  and let's see how these incumbent genes do.
  看看原有基因的收益是什么样的
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  So C is playing against 1 - ε of the population who are playing C
  选择策略C的个体有1-ε的概率对C
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  and ε who are playing B
  以及ε的概率对策略B
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  and its average payoff?
  它的平均收益是多少
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  Well 1 - ε of the time it'll be matched against essentially itself
  1-ε的概率下对自己的策略C
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  and get a payoff of 0,
  此情况的收益是0