1 00:00:00,0 --> 00:00:00,890 Morning, afternoon, evening. Games Without Chance, and week seven, and 2 00:00:00,890 --> 00:00:01,785 we want to talk about mean values, hot, cold, sente, gote. 3 00:00:01,785 --> 00:00:13,84 So and if you have a Japanese dictionary, you can look up the last two terms. 4 00:00:13,84 --> 00:00:21,584 Alright. Mean values one thing we look at a little 5 00:00:21,584 --> 00:00:30,347 while ago at least in some of the extra problems were these games, for instance, 6 00:00:30,347 --> 00:00:44,358 like uh,[SOUND], these, up, and these are games called check games, cashing checks. 7 00:00:44,358 --> 00:00:49,112 And in these games, people want to play it. 8 00:00:49,112 --> 00:00:54,660 By, when you played sums of these games, people grabbed the games. 9 00:00:54,660 --> 00:00:58,300 If this is the game g, and you play g plus g plus g, if you played sums of 10 00:00:58,300 --> 00:01:02,395 these, they behave just like numbers, or very much like numbers, or close to 11 00:01:02,395 --> 00:01:07,410 numbers. this can be generalized. 12 00:01:07,410 --> 00:01:10,725 There's actually a theorem behind all this. 13 00:01:10,725 --> 00:01:17,610 which is called the mean value theorem. although not the same one as in calculus. 14 00:01:17,610 --> 00:01:22,455 And so given again there's a number M of G called the mean value of G. 15 00:01:22,455 --> 00:01:26,610 Such that oh, when a number K independent of N. 16 00:01:26,610 --> 00:01:32,439 Such that when you add up Gn times that this minus n times the mean value if this 17 00:01:32,439 --> 00:01:40,874 is whether a bound which doesn't depend on n over multiple of the mean value. 18 00:01:40,874 --> 00:01:49,23 So, so large numbers of copies of G played together behave approximately. 19 00:01:49,23 --> 00:01:54,628 Like a number and as n gets large k is, doesn't depend on n so k is small 20 00:01:54,628 --> 00:02:00,708 relative to n, so as n gets large this approximation gets better and better at 21 00:02:00,708 --> 00:02:07,928 least relatively, this is called the mean value term and, analysis of this together 22 00:02:07,928 --> 00:02:14,198 with, with an actual construction of, of, of the calculation of this mean value 23 00:02:14,198 --> 00:02:28,363 called the thermograph allows us of, of to have a number of strategies that. 24 00:02:28,363 --> 00:02:32,906 Are not optimum but are actually computable and in some sense, within a 25 00:02:32,906 --> 00:02:37,988 bound of being optimum, that is they're not necessarily optimum strategy, but 26 00:02:37,988 --> 00:02:46,166 they're guaranteed to be not too bad. And these are often based on, you have a 27 00:02:46,166 --> 00:02:52,758 sum of a large number of games, and then the real question in terms of playing a 28 00:02:52,758 --> 00:03:01,140 game decently is which one to play in. So you have a sum of all these games. 29 00:03:01,140 --> 00:03:06,93 Do we play G2 first, or GN, or G1 or whatever? 30 00:03:06,93 --> 00:03:11,735 And if, our opponent plays in G2, should we respond in G2 or go to a different 31 00:03:11,735 --> 00:03:18,944 game? And so this is our Japanese term sente 32 00:03:18,944 --> 00:03:24,652 gote. Sente means to have Sente means you play 33 00:03:24,652 --> 00:03:31,248 a move and you force your opponent. You have the initiative. 34 00:03:31,248 --> 00:03:35,868 The opponent has to respond to your move, Go Tay is the opposite where you play and 35 00:03:35,868 --> 00:03:40,254 your, your opponent can play in some other game. 36 00:03:40,254 --> 00:03:46,39 So, in Sente, you play for instance in G2, your opponent is asked to respond 37 00:03:46,39 --> 00:03:52,707 there immediately. in Gotay may be you play G2 no problem I 38 00:03:52,707 --> 00:03:58,898 play in G5 over here. So there is whole class of strategies and 39 00:03:58,898 --> 00:04:07,270 approximate strategies and interesting Constructions, having to do with the mean 40 00:04:07,270 --> 00:04:12,94 value and various ways of finding it, which give rise to approximate strategies 41 00:04:12,94 --> 00:04:16,558 for playing game and analyst, and analysis of whether you have Sente or 42 00:04:16,558 --> 00:04:22,3 Gote. Okay, next time.