1 00:00:00,000 --> 00:00:02,468 hi again folks so let's talk a little 大家好,再说一遍 2 00:00:02,669 --> 00:00:03,879 bit about a folk theorem now for a 现在谈谈一个民间定理 3 00:00:04,080 --> 00:00:05,469 discounted repeated game so we're in the 打折重复游戏,所以我们在 4 00:00:05,669 --> 00:00:08,169 case where there's a discount factor and 有折扣因素的情况下 5 00:00:08,369 --> 00:00:10,149 people care more about today than the 人们比今天更关心 6 00:00:10,349 --> 00:00:13,750 future or tomorrow and so forth and we 未来或明天等等,我们 7 00:00:13,949 --> 00:00:17,320 want to think about the expansion of the 想考虑的扩展 8 00:00:17,519 --> 00:00:19,510 logic that we just went through and some 我们刚刚经历的逻辑和一些 9 00:00:19,710 --> 00:00:21,970 examples but see whether that holds in a 例子,但看看是否在 10 00:00:22,170 --> 00:00:25,539 general setting of repeated games so 重复游戏的一般设置 11 00:00:25,739 --> 00:00:26,859 what's the folk theorem what's the 民间定理是什么 12 00:00:27,059 --> 00:00:30,728 extension to repeated games so take a 扩展到重复游戏,因此 13 00:00:30,928 --> 00:00:34,239 normal forma game and so there's 正常的形式游戏,所以有 14 00:00:34,439 --> 00:00:36,969 actually very many versions of folk 其实民间的版本很多 15 00:00:37,170 --> 00:00:38,559 theorems and we'll do a very particular 定理,我们将做一个非常特别的 16 00:00:38,759 --> 00:00:41,198 one which has I think the basic 我认为基本的 17 00:00:41,399 --> 00:00:43,779 intuition behind it and a fairly simple 背后的直觉和相当简单 18 00:00:43,979 --> 00:00:46,599 proof so the idea is is we're looking at 证明,所以我们的想法是 19 00:00:46,799 --> 00:00:49,419 some Nash equilibrium of the stage game 阶段游戏的纳什均衡 20 00:00:49,619 --> 00:00:52,448 so take a stage game find a profile 所以参加一个舞台游戏找到一个个人资料 21 00:00:52,649 --> 00:00:54,038 which is a Nash equilibrium of the stage 这是阶段的纳什均衡 22 00:00:54,238 --> 00:01:00,099 game and then also look for some 游戏,然后还寻找一些 23 00:01:00,299 --> 00:01:02,169 alternative strategy and here we have a 另类策略,在这里我们有一个 24 00:01:02,369 --> 00:01:04,149 couple of typos that should be in a 错别字应该在 25 00:01:04,349 --> 00:01:07,769 prime so look for some alternative 总理,所以寻找一些替代方案 26 00:01:07,969 --> 00:01:12,039 strategy a prime such that everybody 策略素数,使每个人 27 00:01:12,239 --> 00:01:14,829 gets a strictly higher payoff from a 从中获得更高的收益 28 00:01:15,030 --> 00:01:19,778 prime than a ok where a is the Nash 优胜于OK,那是纳什 29 00:01:19,978 --> 00:01:22,418 equilibrium then there exists some 平衡,然后存在一些 30 00:01:22,618 --> 00:01:25,959 discount factor below one such that if 低于1的折现系数,如果 31 00:01:26,159 --> 00:01:28,058 everybody has a discount factor above 每个人都有一个以上的折扣系数 32 00:01:28,259 --> 00:01:30,640 that level then there exists a sub-game 那个水平,然后有一个子游戏 33 00:01:30,840 --> 00:01:33,189 perfect equilibrium of the infinite 无限的完美平衡 34 00:01:33,390 --> 00:01:35,799 repetition of the game that has a prime 具有质数的游戏的重复 35 00:01:36,000 --> 00:01:37,840 played in every period on the 在每个时期都玩过 36 00:01:38,040 --> 00:01:39,549 equilibrium path so what this is telling 平衡路径,这说明了什么 37 00:01:39,750 --> 00:01:42,099 us is the logic that we went through in 我们是我们经历的逻辑 38 00:01:42,299 --> 00:01:43,988 those two examples of prisoners dilemmas 那两个囚徒困境的例子 39 00:01:44,188 --> 00:01:46,179 where we found the discount factory 我们找到折扣工厂的地方 40 00:01:46,379 --> 00:01:50,829 there half or at least 7 9 etc take any 有一半或至少7 9等采取任何 41 00:01:51,030 --> 00:01:53,679 game find a Nash equilibrium of that and 游戏找到那个的纳什均衡 42 00:01:53,879 --> 00:01:55,448 find something which is better than that 找到比这更好的东西 43 00:01:55,649 --> 00:01:57,488 which you'd like to sustain in an 您想维持在 44 00:01:57,688 --> 00:01:59,140 infinitely repeated game and you can do 无限重复的游戏,你可以做 45 00:01:59,340 --> 00:02:00,939 the same logic that we did in those 与我们在那些逻辑中所做的相同的逻辑 46 00:02:01,140 --> 00:02:03,579 examples in the general case where 一般情况下的例子 47 00:02:03,780 --> 00:02:04,840 there'll be a high enough discount 会有足够高的折扣 48 00:02:05,040 --> 00:02:07,539 factor that'll make that sustainable ok 使可持续发展的因素 49 00:02:07,739 --> 00:02:10,029 and and basically the proof of this 并基本上证明了这一点 50 00:02:10,229 --> 00:02:13,630 theorem is is very similar to what we 定理与我们非常相似 51 00:02:13,830 --> 00:02:15,640 went through in those examples so the 经历了那些例子,所以 52 00:02:15,840 --> 00:02:17,439 idea is is you know we'll play a prime 想法是你知道我们会发挥主要作用 53 00:02:17,639 --> 00:02:19,570 as long as everybody plays it 只要大家玩 54 00:02:19,770 --> 00:02:21,910 if anybody deviates from that then we're 如果有人偏离了那我们 55 00:02:22,110 --> 00:02:23,230 gonna go to a grim trigger we're just 要去一个严峻的触发,我们只是 56 00:02:23,430 --> 00:02:24,850 gonna threaten to play the Nash 威胁要打纳什 57 00:02:25,050 --> 00:02:26,920 equilibrium a forever after which is 永远平衡之后 58 00:02:27,120 --> 00:02:28,870 giving us a lower payoff than a prime 给我们的回报比素数低 59 00:02:29,069 --> 00:02:30,550 and we just need to make sure that 我们只需要确保 60 00:02:30,750 --> 00:02:32,469 people care enough about the loss of the 人们足够在意损失 61 00:02:32,669 --> 00:02:35,170 future to offset the game the game from 未来来抵消游戏 62 00:02:35,370 --> 00:02:37,570 today so in terms of the the proof 今天,就证明而言 63 00:02:37,770 --> 00:02:39,370 checking that this is a sub-game 检查这是一个子游戏 64 00:02:39,569 --> 00:02:41,080 equilibrium for high enough discount 足够高的折扣的均衡 65 00:02:41,280 --> 00:02:43,380 factors what do we have to do well 因素我们要做好什么 66 00:02:43,580 --> 00:02:46,420 playing a forever if everyone anyone is 如果每个人都在玩一个永远 67 00:02:46,620 --> 00:02:48,550 ever deviated is part of a sub-game 曾经偏离的游戏是子游戏的一部分 68 00:02:48,750 --> 00:02:50,439 perfect continuation if we ever have a 如果我们有一个完美的延续 69 00:02:50,639 --> 00:02:52,480 deviation because it's Nash in every sub 偏差,因为它是每个子项中的纳什 70 00:02:52,680 --> 00:02:56,590 game so we need to check will anybody 游戏,所以我们需要检查任何人 71 00:02:56,789 --> 00:02:58,780 want to deviate from a prime if nobody 如果没有人想偏离素数 72 00:02:58,979 --> 00:03:02,590 has in the past and we can bound the 在过去,我们可以绑定 73 00:03:02,789 --> 00:03:04,900 game so an upper bound on the gain is 游戏,所以收益的上限是 74 00:03:05,099 --> 00:03:07,300 the maximum over all players and all 所有玩家和所有玩家的最大值 75 00:03:07,500 --> 00:03:09,100 possible deviations they could have of 他们可能会有的偏差 76 00:03:09,300 --> 00:03:12,280 the best of the gain and payoff that 最好的收益和回报 77 00:03:12,479 --> 00:03:14,530 they would get from that so that gives 他们会从中得到,所以给 78 00:03:14,729 --> 00:03:18,759 us a maximum possible gain the minimum 我们最大可能获得最小 79 00:03:18,959 --> 00:03:21,640 period per period loss so this is the 每个时期的损失,所以这是 80 00:03:21,840 --> 00:03:23,319 maximum they can gain from today well 他们今天最大的收获就是 81 00:03:23,519 --> 00:03:24,730 compared to the minimum they could lose 与他们可能损失的最低赔率相比 82 00:03:24,930 --> 00:03:25,660 from tomorrow 从明天起 83 00:03:25,860 --> 00:03:28,469 so the minimum they could lose is 因此他们可能损失的最低金额是 84 00:03:28,669 --> 00:03:30,939 instead of getting a prime they're not 而不是得到一个素数,他们不是 85 00:03:31,139 --> 00:03:35,319 going to go to a so that's that and and 去一个就是这样,并且 86 00:03:35,519 --> 00:03:37,330 take that the minimum across different 把不同的最小值 87 00:03:37,530 --> 00:03:39,580 players for this and one question is 玩家对此,一个问题是 88 00:03:39,780 --> 00:03:42,009 sort of why this the question here is 有点为什么这是这里的问题 89 00:03:42,209 --> 00:03:46,930 you know is really the minimum relative 你知道真的是最小的亲戚 90 00:03:47,129 --> 00:03:48,610 to the Nash equilibrium or could they 到纳什均衡还是 91 00:03:48,810 --> 00:03:50,969 gain so think about this a little bit 获得,所以请对此一点点思考 92 00:03:51,169 --> 00:03:53,380 why wouldn't they want to change from 他们为什么不想要从 93 00:03:53,580 --> 00:03:55,390 the Nash equilibrium in the future right 未来权利中的纳什均衡 94 00:03:55,590 --> 00:03:57,520 so the idea there is there they're not 所以那里没有他们的想法 95 00:03:57,719 --> 00:04:00,730 going to be able to to help themselves 能够自助 96 00:04:00,930 --> 00:04:02,830 by trying to change away from the 通过尝试改变 97 00:04:03,030 --> 00:04:04,660 punishment because that is a Nash 惩罚,因为那是纳什 98 00:04:04,860 --> 00:04:05,950 equilibrium so they're already getting 平衡,所以他们已经在 99 00:04:06,150 --> 00:04:07,900 the best possible payoff if the other 最好的回报,如果其他 100 00:04:08,099 --> 00:04:09,069 people follow through with the 人们遵循 101 00:04:09,269 --> 00:04:11,860 punishment so we've got the maximum 惩罚,所以我们得到了最大的 102 00:04:12,060 --> 00:04:14,550 possible game the minimum possible loss 可能的游戏最小可能的损失 103 00:04:14,750 --> 00:04:17,528 so if I deviate and given what other 所以如果我偏离并给了其他 104 00:04:17,728 --> 00:04:20,468 players are doing the maximum possible 玩家正在尽最大努力 105 00:04:20,668 --> 00:04:23,528 net gain overall is our gain the M today 总体净收益是我们今天的收益M 106 00:04:23,728 --> 00:04:27,100 but I could lose up to M tomorrow 但明天我可能输给M 107 00:04:27,300 --> 00:04:29,499 in the future I'll lose at least them in 将来我至少会失去他们 108 00:04:29,699 --> 00:04:33,550 the future and this should be an AI then 未来,这应该是一个人工智能 109 00:04:33,750 --> 00:04:36,730 we've got beta I over 1 minus beta I and 我们的Beta I超过1减去Beta I,并且 110 00:04:36,930 --> 00:04:41,350 so if you go ahead and you know set this 因此,如果您继续进行,并且知道设置 111 00:04:41,550 --> 00:04:47,290 has to be non-negative sorry has to be 必须是非负的,对不起 112 00:04:47,490 --> 00:04:49,749 negative in order for players not to 消极的,以使球员不 113 00:04:49,949 --> 00:04:52,749 want to deviate so what do we need we 想偏离,所以我们需要什么 114 00:04:52,949 --> 00:04:56,379 need that M is less than or equal to 需要M小于或等于 115 00:04:56,579 --> 00:04:58,959 this so M over m is less than or equal 因此,M大于m小于或等于 116 00:04:59,158 --> 00:05:03,939 to beta I over 1 minus beta I and that 超过1的beta I减去beta I, 117 00:05:04,139 --> 00:05:06,790 gives us a lower bound on beta I it has 给了我们它的beta的下限 118 00:05:06,990 --> 00:05:10,480 to be at least M over m plus m so that's 至少M超过m加m,所以 119 00:05:10,680 --> 00:05:12,850 a not a tight lower bound in the sense 从某种意义上讲不是一个严格的下限 120 00:05:13,050 --> 00:05:15,670 that we went with fairly loose bounds 我们的界限相当宽松 121 00:05:15,870 --> 00:05:18,459 here but if everybody has a high enough 在这里,但如果每个人都足够高 122 00:05:18,658 --> 00:05:20,588 discount factor then you can sustain 折扣系数,那么您可以维持 123 00:05:20,788 --> 00:05:22,360 cooperation so this is just a 合作,所以这只是一个 124 00:05:22,560 --> 00:05:24,430 straightforward generalization of the 的直接概括 125 00:05:24,629 --> 00:05:27,399 examples we looked through before and 我们之前看过的例子 126 00:05:27,598 --> 00:05:30,160 it's showing us that we can sustain 告诉我们我们可以维持 127 00:05:30,360 --> 00:05:32,588 cooperation in an infinitely repeated 合作无限重复 128 00:05:32,788 --> 00:05:35,860 setting this is provided people have 设置这个是提供给人们 129 00:05:36,060 --> 00:05:38,410 enough patience for the future now 现在对未来有足够的耐心 130 00:05:38,610 --> 00:05:41,129 there's many bells and whistles on this 有很多风吹草动 131 00:05:41,329 --> 00:05:44,410 one thing to think about you could you 想一想你能 132 00:05:44,610 --> 00:05:46,509 can sustain fairly complicated play if 可以维持相当复杂的比赛,如果 133 00:05:46,709 --> 00:05:48,160 you if you'd like so let's take a look 如果您愿意的话,让我们看一下 134 00:05:48,360 --> 00:05:50,889 at the game we looked at before so the 在我们之前看过的游戏中, 135 00:05:51,089 --> 00:05:52,360 prisoner's dilemma but now we've got 囚徒的困境,但现在我们有了 136 00:05:52,560 --> 00:05:55,749 this very high payoff from deviating one 从偏离中获得很高的回报 137 00:05:55,949 --> 00:05:58,480 thing you can notice is the total of the 您可以注意到的是 138 00:05:58,680 --> 00:06:00,850 payoffs here the players together get 玩家们在这里得到的回报 139 00:06:01,050 --> 00:06:05,800 ten if they cooperate they're only 十,如果他们合作,他们只是 140 00:06:06,000 --> 00:06:08,949 getting six in total so here actually 一共六个 141 00:06:09,149 --> 00:06:12,309 playing this makes one of the players 玩这个使球员之一 142 00:06:12,509 --> 00:06:14,829 really well off so if they played this 真的很好,所以如果他们玩这个 143 00:06:15,028 --> 00:06:16,360 in perpetuity they get three three 他们永远得到三三 144 00:06:16,560 --> 00:06:19,149 suppose they trying to do following they 假设他们试图跟随他们 145 00:06:19,348 --> 00:06:23,290 say in odd periods we'll play a CD right 说在奇怪的时期我们会播放CD权利 146 00:06:23,490 --> 00:06:27,129 so in in periods one three five and so 所以在一期三五等 147 00:06:27,329 --> 00:06:29,499 forth will play cooperate by the first 第四将发挥合作的第一 148 00:06:29,699 --> 00:06:31,869 player defect for the other so the 另一个玩家的缺陷 149 00:06:32,069 --> 00:06:33,249 second player is going to get tens in 第二个玩家将获得 150 00:06:33,449 --> 00:06:36,069 those periods but then we'll play will 那些时期,但是我们将演奏 151 00:06:36,269 --> 00:06:39,340 reverse it and the even periods 扭转它和偶数期 152 00:06:39,540 --> 00:06:42,280 right so now roughly on average players 现在大概是普通玩家 153 00:06:42,480 --> 00:06:44,350 are getting five each instead of three 每人得到五个而不是三个 154 00:06:44,550 --> 00:06:47,710 each right so what we'll do is what 每一项权利,所以我们要做的是 155 00:06:47,910 --> 00:06:49,540 we'll alternate and as long as we're 我们会交替,只要我们 156 00:06:49,740 --> 00:06:51,670 you're continuing to abide by these 你继续遵守这些 157 00:06:51,870 --> 00:06:56,079 rules where we nicely do this then in in 规定我们在哪里做的很好 158 00:06:56,279 --> 00:07:00,009 the future as long as everybody does 只要每个人都做的未来 159 00:07:00,209 --> 00:07:01,600 this we'll continue to do it 这我们会继续做 160 00:07:01,800 --> 00:07:03,520 if anybody deviates from this then we'll 如果有人偏离这一点,那么我们将 161 00:07:03,720 --> 00:07:05,800 just go to defect defect right and you 只是去缺陷缺陷吧,你 162 00:07:06,000 --> 00:07:07,660 can check and see what kinds of discount 可以检查看看有哪些折扣 163 00:07:07,860 --> 00:07:10,060 factors you need and you know are there 你需要的因素,你知道在那里 164 00:07:10,259 --> 00:07:11,470 different discount factors you need for 您需要的不同折扣系数 165 00:07:11,670 --> 00:07:12,790 the first player that the player is 该玩家是的第一个玩家 166 00:07:12,990 --> 00:07:14,050 getting the CD in the first period 在第一期获得CD 167 00:07:14,250 --> 00:07:16,210 versus the second player and so forth 与第二个玩家等 168 00:07:16,410 --> 00:07:18,100 you can go through that and actually 你可以经历一下,实际上 169 00:07:18,300 --> 00:07:22,870 this kind of thing is is something that 这种事情是 170 00:07:23,069 --> 00:07:25,180 people worry about in regulatory 人们担心监管 171 00:07:25,379 --> 00:07:29,170 settings so for instance you know 设置,例如,您知道 172 00:07:29,370 --> 00:07:31,210 imagine that you have a situation where 想象你有一种情况 173 00:07:31,410 --> 00:07:33,759 you've got companies bidding for 你有公司竞标 174 00:07:33,959 --> 00:07:34,930 government contracts and they're 政府合同,他们是 175 00:07:35,129 --> 00:07:36,220 repeating you know they're doing this 再说一遍,你知道他们正在这样做 176 00:07:36,420 --> 00:07:39,819 repeatedly over time and one way they 随着时间的推移反复出现,一种方法是 177 00:07:40,019 --> 00:07:42,370 could do it is to say okay look we can 可以说是可以的,我们可以 178 00:07:42,569 --> 00:07:44,199 compete against each other and bid very 互相竞争并非常出价 179 00:07:44,399 --> 00:07:48,160 high every day or have to bid you know 每天都很高,或者必须出价 180 00:07:48,360 --> 00:07:49,750 to give them a the government of low 给他们一个低下的政府 181 00:07:49,949 --> 00:07:51,750 cost every day if there's a procurement 如果有采购,每天都会花费 182 00:07:51,949 --> 00:07:54,879 contract but what they could do 合同,但他们能做什么 183 00:07:55,079 --> 00:07:57,160 alternatively is say okay look I'll let 或者说好吧,我会让 184 00:07:57,360 --> 00:08:00,850 you in the contract today you let me win 你今天的合同,你让我赢 185 00:08:01,050 --> 00:08:02,710 it tomorrow and we'll just alternate and 明天,我们将轮流和 186 00:08:02,910 --> 00:08:04,720 as long as we keep cooperating we won't 只要我们保持合作,我们就不会 187 00:08:04,920 --> 00:08:06,520 compete with each other we'll enjoy high 相互竞争,我们将享受高 188 00:08:06,720 --> 00:08:09,550 payoffs but if that ever breaks down 回报,但如果失败了 189 00:08:09,750 --> 00:08:11,680 then we're gonna go back to competition 然后我们要回到竞争 190 00:08:11,879 --> 00:08:14,770 so there's situations where regulators 因此,在某些情况下,监管机构 191 00:08:14,970 --> 00:08:18,189 worry and in fact there's some various 担心,实际上有一些 192 00:08:18,389 --> 00:08:20,610 cases that have some evidence that 有证据表明 193 00:08:20,810 --> 00:08:23,829 companies will tend to do this to try 公司将倾向于这样做尝试 194 00:08:24,029 --> 00:08:26,139 and game the system and an increase 和游戏系统,并增加 195 00:08:26,339 --> 00:08:28,270 payoff so so you can see that the kind 回报,所以你可以看到那种 196 00:08:28,470 --> 00:08:29,949 of logic and what has to be true in 逻辑和什么必须是真实的 197 00:08:30,149 --> 00:08:31,139 order for that to happen 为了做到这一点 198 00:08:31,339 --> 00:08:33,490 okay so repeated games we've had a 好吧,如此反复的比赛,我们有一个 199 00:08:33,690 --> 00:08:36,789 fairly detailed look at these things 比较详细地看这些东西 200 00:08:36,990 --> 00:08:39,759 players can condition their future play 玩家可以限制他们未来的比赛 201 00:08:39,960 --> 00:08:42,099 on past actions that allows them to 根据他们过去的行动 202 00:08:42,299 --> 00:08:43,990 react to things in ways that they can't 以他们无法做到的方式对事物做出反应 203 00:08:44,190 --> 00:08:46,689 in a static game it produces new 在静态游戏中,它会产生新的 204 00:08:46,889 --> 00:08:49,629 equilibria in the game folk theorems 博弈定理中的均衡 205 00:08:49,830 --> 00:08:52,029 partly referring to the fact that these 部分是指这些 206 00:08:52,230 --> 00:08:52,349 were 是 207 00:08:52,549 --> 00:08:53,818 known for a long time in kind of 长期以来以 208 00:08:54,019 --> 00:08:55,469 folklore and game theory before they 民俗学和博弈论 209 00:08:55,669 --> 00:08:57,328 were actually written down 实际上被写下来 210 00:08:57,528 --> 00:08:59,370 there's many equilibria in these things 这些东西之间有很多平衡 211 00:08:59,570 --> 00:09:03,709 and they're based on on key ingredients 它们基于关键成分 212 00:09:03,909 --> 00:09:06,059 having observation of what other players 观察其他玩家 213 00:09:06,259 --> 00:09:09,000 do and being able to react to that and 能够并且能够对此做出反应 214 00:09:09,200 --> 00:09:10,799 having sufficient value in the future 将来有足够的价值 215 00:09:11,000 --> 00:09:13,799 either by limit of the means which is an 要么通过手段限制 216 00:09:14,000 --> 00:09:15,389 extreme value or high enough discount 极高价值或足够高的折扣 217 00:09:15,589 --> 00:09:17,159 factors so that players really care 使玩家真正关心的因素 218 00:09:17,360 --> 00:09:20,189 about the future now repeated games have 关于未来现在重复的游戏有 219 00:09:20,389 --> 00:09:21,599 actually been a fairly active area of 实际上是一个相当活跃的领域 220 00:09:21,799 --> 00:09:23,279 research recently there's a lot of other 最近的研究还有很多其他的 221 00:09:23,480 --> 00:09:25,439 interesting questions on these what 关于这些有趣的问题是什么 222 00:09:25,639 --> 00:09:27,359 happens if you don't always see what 如果您不总是看到什么就会发生 223 00:09:27,559 --> 00:09:29,219 other players do you only see sometimes 其他玩家您有时只会看到 224 00:09:29,419 --> 00:09:32,370 there's some noises and things what 有一些噪音和其他东西 225 00:09:32,570 --> 00:09:35,519 happens if there's uncertain payoffs 如果不确定的回报会发生 226 00:09:35,720 --> 00:09:38,689 over time there are payoffs are varying 随着时间的流逝,收益是不同的 227 00:09:38,889 --> 00:09:41,429 there's a whole series of issues there 那里有一系列的问题 228 00:09:41,629 --> 00:09:43,349 there's also issues about things like 还有一些类似的问题 229 00:09:43,549 --> 00:09:48,359 renegotiation so you know the logic here 重新谈判,所以你知道这里的逻辑 230 00:09:48,559 --> 00:09:51,508 has been okay if if we anybody ever 如果我们有人曾经一直没事 231 00:09:51,708 --> 00:09:54,539 deviates then we go to a bad equilibrium 偏离然后我们达到一个糟糕的平衡 232 00:09:54,740 --> 00:09:58,709 forever after so suppose that happens 如此假设之后永远 233 00:09:58,909 --> 00:10:01,740 somebody deviates and then we you know 有人偏离,然后我们知道 234 00:10:01,940 --> 00:10:03,779 after about a few periods we say well 大约过了一段时间后,我们说好了 235 00:10:03,980 --> 00:10:05,578 this is kind of silly why are we why are 这有点傻,为什么我们为什么 236 00:10:05,778 --> 00:10:07,828 we hurting ourselves let's go back to 我们伤害自己让我们回到 237 00:10:08,028 --> 00:10:09,419 the original agreement let's forget 原始协议让我们忘记 238 00:10:09,620 --> 00:10:12,689 about things by Ron's be bygones so we 关于罗恩(Ron)过去的事情,所以我们 239 00:10:12,889 --> 00:10:14,189 can do better by just starting all over 可以从头开始做得更好 240 00:10:14,389 --> 00:10:18,209 right okay well that's wonderful the 好吧,那太好了 241 00:10:18,409 --> 00:10:20,758 difficulty is that if if we now believe 困难在于如果我们现在相信 242 00:10:20,958 --> 00:10:24,389 that if we deviate eventually we're 如果我们最终偏离了我们 243 00:10:24,589 --> 00:10:26,370 going to be forgiven then that changes 将被原谅,然后改变 244 00:10:26,570 --> 00:10:28,469 the whole nature of the game and changes 游戏的整体性质和变化 245 00:10:28,669 --> 00:10:30,719 the the the incentives at the beginning 一开始的激励措施 246 00:10:30,919 --> 00:10:33,419 and so incorporating that kind of logic 所以结合了这种逻辑 247 00:10:33,620 --> 00:10:36,240 is is quite complicated and another area 是相当复杂的另一个领域 248 00:10:36,440 --> 00:10:38,519 of research and in these so repeated 研究,并在这些如此重复 249 00:10:38,720 --> 00:10:39,959 games are very interesting they have 游戏非常有趣 250 00:10:40,159 --> 00:10:42,029 lots of applications there's some 很多应用程序中有一些 251 00:10:42,230 --> 00:10:43,620 interesting logic which comes out of 有趣的逻辑 252 00:10:43,820 --> 00:10:45,748 them sometimes you can sustain 他们有时你可以维持 253 00:10:45,948 --> 00:10:47,519 cooperation or better payoffs and you 合作或更好的回报,您 254 00:10:47,720 --> 00:10:49,198 can in the static setting sometimes you 可以在静态设置中有时 255 00:10:49,399 --> 00:10:52,169 can't and we've seen some of the 不能,我们已经看到了一些 256 00:10:52,370 --> 00:10:57,370 features that affect that 影响那个的功能