Knowledge (XXG)

Sprague–Grundy theorem

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2498: 66: 2176: 2493:{\displaystyle \color {blue}S\color {black}+\color {red}S'\color {black}={\Big \{}\color {blue}S\color {black}+\color {red}\{*1\}\color {black}{\Big \}}\cup {\Big \{}\color {red}S'\color {black}+\color {blue}\{*1,\{*1\},*2\}\color {black},\color {red}S'\color {black}+\color {blue}\{*2,\{*1,\{*1\},*2\}\}\color {black},\color {red}S'\color {black}+\color {blue}\{\{*1\},\{\{*1\}\},\{*1,\{*1\},*2\}\}\color {black}{\Big \}}} 25: 128: 2073: 6194:
is called its Grundy value, or Grundy number, and the function that assigns this value to each such position is called the Sprague–Grundy function. R. L. Sprague and P. M. Grundy independently gave an explicit definition of this function, not based on any concept of equivalence to nim positions, and
1811:
Sizes of heaps Moves A B C A' B' C'   1 2 2 1 1 1 Alice takes 1 from A 0 2 2 1 1 1 Bob takes 1 from A' 0 2 2 0 1 1 Alice takes 1 from B' 0 2 2 0 0 1 Bob takes 1 from C' 0 2 2 0 0 0 Alice takes 2 from B 0 0 2 0 0 0 Bob takes 2 from C 0
607:
At step 4, Bob had two options: remove one from B or remove one from C. Note, however, that it didn't really matter which heap Bob removed the object from: Either way, Alice would be left with exactly one object in exactly one pile. So, using our recursive definition, Bob really only has one move:
1202: 425:
is not impartial because, supposing Alice were playing red and Bob were playing black, for any given arrangement of pieces on the board, if it were Alice's turn, she would only be allowed to move the red pieces, and if it were Bob's turn, he would only be allowed to move the black pieces.
414:
is an example of an impartial game. In nim, there are one or more heaps of objects, and two players (we'll call them Alice and Bob), take turns choosing a heap and removing 1 or more objects from it. The winner is the player who removes the final object from the final heap. The game is
238:
of any impartial game is the unique nimber that the game is equivalent to. In the case of a game whose positions are indexed by the natural numbers (like nim itself, which is indexed by its heap sizes), the sequence of nimbers for successive positions of the game is called the
467:
Sizes of heaps Moves A B C   1 2 2 Alice takes 1 from A 0 2 2 Bob takes 1 from B 0 1 2 Alice takes 1 from C 0 1 1 Bob takes 1 from B 0 0 1 Alice takes 1 from C 0 0 0 Bob has no moves, so Alice
1844: 978: 2611: 6415:. Thus, although Sprague and Grundy never explicitly stated the theorem described in this article, it follows directly from their results and is credited to them. These results have subsequently been developed into the field of 2173:, remember that a player can either make a move in the first game, leaving the second game untouched, or make a move in the second game, leaving the first game untouched. So the combined game's starting position is: 3196: 3135: 1660:
Sizes of heaps Moves   A' B' C' 1 1 1 Alice takes 1 from A' 0 1 1 Bob takes one from B' 0 0 1 Alice takes one from C' 0 0 0 Bob has no moves, so Alice
1559:, nimbers can be used to describe the positions of any finite, impartial game, and in fact, the Sprague–Grundy theorem states that every instance of a finite, impartial game can be associated with a 2165: 4857: 971: 421:
because for any given configuration of pile sizes, the moves Alice can make on her turn are exactly the same moves Bob would be allowed to make if it were his turn. In contrast, a game such as
429:
Note that any configuration of an impartial game can therefore be written as a single position, because the moves will be the same no matter whose turn it is. For example, the position of the
4725: 889: 456:, because if it's Alice's turn, she has no moves to make, and if it's Bob's turn, he has no moves to make either. A move can be associated with the position it leaves the next player in. 4556: 2678: 2649: 4969: 4502: 4404: 1546: 4772: 3046: 2106: 6086: 5413: 397: 6052: 5318: 5030: 4639: 4071: 3982: 2882: 6287: 5708: 5522: 5379: 5287: 5232: 4460: 4323: 4239: 4037: 3914: 3858: 3788: 3764: 3708: 3655: 3547: 3431: 3248: 3159: 3098: 3070: 3019: 2997: 2777: 2730: 1839: 146: 5607: 4355: 3300: 1461: 6192: 6115: 4886: 4299: 2068:{\displaystyle \color {blue}S={\Big \{}{\big \{}*1,\{*1\},*2{\big \}},{\big \{}*2,\{*1,\{*1\},*2\}{\big \}},{\big \{}\{*1\},\{\{*1\}\},\{*1,\{*1\},*2\}{\big \}}{\Big \}}} 5885: 5799: 5498: 5355: 5263: 5081: 4159: 4128: 4013: 2962: 2905: 1414: 805: 5684: 5576: 4608: 4580: 5971: 5736: 5656: 5441: 5208: 5183: 2825: 1801: 1776: 1751: 1650: 1625: 1600: 1487: 5915: 5852: 5766: 5158: 713: 658: 579: 6018: 5108: 4996: 4436: 3890: 3740: 3631: 3463: 3358: 6393: 1376: 493: 454: 6364: 4215: 4189: 4097: 3940: 3814: 3684: 3599: 3573: 3407: 3326: 2931: 6240: 5938: 5822: 5548: 5464: 2753: 2706: 1353: 1310: 1279: 1256: 1233: 828: 763: 740: 684: 629: 602: 546: 516: 6413: 6338: 6318: 6260: 6217: 6163: 6143: 5991: 5627: 5128: 5050: 4906: 4259: 3834: 3523: 3503: 3483: 3378: 3268: 3224: 2851: 2800: 1726: 1706: 1686: 1330: 341: 321: 1197:{\displaystyle {\Big \{}{\big \{}*1,\{*1\},*2{\big \}},{\big \{}*2,\{*1,\{*1\},*2\}{\big \}},{\big \{}\{*1\},\{\{*1\}\},\{*1,\{*1\},*2\}{\big \}}{\Big \}}.} 38: 4653:. The more specific result, that the given game's initial position must be equivalent to a nimber, shows that the game is itself equivalent to a nimber. 6431:
and others, where they are now encapsulated in the Sprague–Grundy theorem and its proof in the form described here. The field is presented in the books
7760: 6530: 6433: 227:, the value of that one-heap game in an algebraic system whose addition operation combines multiple heaps to form a single equivalent heap in nim. 2111: 6693: 897: 7592: 87: 3164: 2505: 663:
At step 3, Alice had 3 options: remove two from C, remove one from C, or remove one from B. Removing two from C leaves Bob in position
7755: 7409: 6944: 6742: 7228: 7047: 182: 164: 109: 52: 6849: 3103: 44: 7318: 459:
Doing so allows positions to be defined recursively. For example, consider the following game of Nim played by Alice and Bob.
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is one in which at any given point in the game, each player is allowed exactly the same set of moves. Normal-play
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At step 5, Alice had exactly one option: to remove one object from heap C, leaving Bob with no moves. Since her
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The Sprague–Grundy theorem and its proof encapsulate the main results of a theory discovered independently by
7709: 7308: 7278: 6934: 6722: 7643: 7734: 7714: 7694: 7313: 7218: 7077: 7027: 7022: 6954: 6924: 6844: 6772: 6659: 6521: 4728: 4261:, the previous player can respond with the same move in the other copy, and so always make the last move. 1492: 251: 208: 4734: 6752: 4507: 715:, as described in step 4. However, removing 1 from B would leave Bob with two objects in a single pile. 7193: 7178: 4360: 346: 7527: 7512: 7399: 7394: 7298: 7283: 7248: 7213: 6812: 6757: 6679: 6481: 6439: 4650: 4583: 303:
to be the two-player game where neither player has any legal moves. Referring to the two players as
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Schleicher, Dierk; Stoll, Michael (2006). "An introduction to Conway's games and numbers".
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objects in exactly one heap. Formally, nimbers are defined inductively as follows:
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As an intermediate step to proving the main theorem, we show that for every position
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games above, we can show that on every turn, Alice has a move that forces Bob into a
7582: 7577: 7432: 7007: 6650: 6629: 6608: 6452: 686:. Removing one from C leaves Bob with two piles, each of size one, i.e., position 4562:
and commutativity, the right-hand sides of these results are equal. Furthermore,
6539: 7699: 7502: 7497: 7477: 7273: 7258: 7067: 7037: 6972: 6962: 6792: 6727: 6703: 5940:; in either case the result is a position plus itself. (It is not possible that 215:, or to an infinite generalization of nim. It can therefore be represented as a 1577:
their positions together. For example, consider another game of nim with heaps
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holds. By the above definition of equivalence, this amounts to showing that
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Every impartial game position is equivalent to a position in the game of nim
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because equality is an equivalence relation on outcome classes. Via the
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is added to them, they are always in the same outcome class. Formally,
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At step 6 of the game (when all of the heaps are empty) the position is
280:(all games come to an end: there are no infinite lines of play) and the 7389: 7379: 7057: 6293: 6292:
The Grundy value of the sum of a finite set of positions is just the
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Finally, suppose instead that the next player moves in the component
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corresponds to the position in a game of nim where there are exactly
1284: 224: 6395:, and therefore belongs to the same outcome class, for any position 3766:-position, because the next player has a winning strategy: choose a 6635:
Easily readable, introductory account from the UCLA Math Department
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It follows straightforwardly from these results that if a position
5415:. We do so by giving an explicit strategy for the previous player. 7158: 3191:{\displaystyle \color {blue}S\color {black}\approx \color {red}S'} 2606:{\displaystyle S+S'=\{S+s'\mid s'\in S'\}\cup \{s+S'\mid s\in S\}} 5527:
Or consider the case that the next player moves in the component
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options, and we conclude from the previous paragraph that adding
2665: 2636: 2613:, which means that addition is both commutative and associative. 894:
Following the same recursive logic, at step 2, Bob's position is
495:, because Bob has no valid moves to make. We name this position 6558:
Smith, Cedric A.B. (1960), "Patrick Michael Grundy, 1917–1959",
5381:-position, which, using the second lemma once again, means that 3433:-position. Then the previous player has a winning strategy for 6675: 4971:, that is, the smallest non-negative integer not equal to some 411: 212: 121: 59: 18: 2627:: either the next player (the one whose turn it is) wins (an 6274: 5695: 5509: 5366: 5274: 5219: 4447: 4310: 4226: 4024: 3901: 3845: 3775: 3751: 3695: 3642: 3534: 3418: 3235: 3146: 3085: 3057: 2984: 2764: 2717: 299:
they are allowed to make. As an example, we can define the
219:, the size of the heap in its equivalent game of nim, as an 5052:
is zero, the claim is trivially true. Otherwise, consider
3130:{\displaystyle \color {blue}S\color {black}+\color {red}S'} 4649:
We prove that all positions are equivalent to a nimber by
4325:-position by hypothesis, it follows from the first lemma, 6265:
A position is a loss for the next player to move (i.e. a
5234:-position by the lemma's forward implication. Therefore, 5289:-position, and, citing the lemma's reverse implication, 4462:-position, it follows from the first lemma in the form 2160:{\displaystyle \color {red}S'={\Big \{}\{*1\}{\Big \}}.} 399:, since the set of moves each player can make is empty. 262:
For the purposes of the Sprague–Grundy theorem, a
6289:-position) if and only if its Grundy value is zero; and 6145:
is a position of an impartial game, the unique integer
5686:. And, as shown before, any position plus itself is a 142: 6643: 966:{\displaystyle {\big \{}\{*1,\{*1\},*2\},*2{\big \}}.} 830:. Alice's position is then the set of all her moves: 223:
in the infinite generalization, or alternatively as a
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To use our running examples, notice that in both the
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may be too technical for most readers to understand
6560:Journal of the Royal Statistical Society, Series A 6407: 6387: 6358: 6332: 6312: 6281: 6254: 6234: 6211: 6186: 6157: 6137: 6109: 6080: 6046: 6012: 5985: 5965: 5932: 5909: 5879: 5846: 5816: 5793: 5760: 5730: 5702: 5678: 5650: 5621: 5601: 5570: 5542: 5516: 5492: 5458: 5435: 5407: 5373: 5349: 5312: 5281: 5257: 5226: 5202: 5177: 5152: 5122: 5102: 5075: 5044: 5024: 4990: 4963: 4900: 4880: 4851: 4766: 4719: 4633: 4602: 4574: 4550: 4496: 4454: 4430: 4398: 4349: 4317: 4293: 4253: 4233: 4209: 4183: 4153: 4122: 4091: 4065: 4031: 4007: 3976: 3945:As these are the only two cases, the lemma holds. 3934: 3908: 3884: 3852: 3828: 3808: 3782: 3758: 3734: 3702: 3678: 3649: 3625: 3593: 3567: 3541: 3517: 3497: 3477: 3457: 3425: 3401: 3372: 3352: 3320: 3294: 3262: 3242: 3218: 3190: 3161:-position, which as we will see in Lemma 2, means 3153: 3129: 3092: 3064: 3040: 3013: 2991: 2956: 2925: 2899: 2876: 2845: 2819: 2794: 2771: 2747: 2724: 2700: 2672: 2643: 2605: 2492: 2159: 2100: 2067: 1833: 1795: 1770: 1745: 1720: 1700: 1680: 1644: 1619: 1594: 1540: 1481: 1455: 1408: 1370: 1347: 1324: 1304: 1273: 1250: 1227: 1196: 965: 883: 822: 799: 757: 734: 707: 678: 652: 623: 596: 573: 540: 510: 487: 448: 391: 335: 315: 5633:excluded number, the previous player can move in 2465: 2242: 2232: 2203: 2148: 2129: 2059: 1857: 1186: 984: 3072:-positions. (Notice that in the combined game, 1815:To differentiate between the two games, for the 1812:0 0 0 0 0 Alice has no moves, so Bob wins. 4720:{\displaystyle G=\{G_{1},G_{2},\ldots ,G_{k}\}} 4073:. Applying the definition of equivalence with 6199:The Grundy value of a single nim pile of size 4241:-position: for every move made in one copy of 2502:The explicit formula for adding positions is: 884:{\displaystyle {\big \{}*1,\{*1\},*2{\big \}}} 343:(for Bob), we would denote their positions as 6687: 6195:showed that it had the following properties: 4165:of addition) is in the same outcome class as 3601:(which exists for the analogous reason). So 2052: 1973: 1963: 1911: 1901: 1864: 1179: 1100: 1090: 1038: 1028: 991: 955: 903: 876: 839: 8: 6652:Combinatorial Games, Theory and Applications 4846: 4792: 4714: 4669: 2673:{\displaystyle {\boldsymbol {\mathcal {P}}}} 2644:{\displaystyle {\boldsymbol {\mathcal {N}}}} 2600: 2571: 2565: 2526: 2459: 2456: 2444: 2435: 2423: 2417: 2414: 2405: 2402: 2396: 2387: 2384: 2363: 2360: 2348: 2339: 2327: 2315: 2294: 2282: 2273: 2261: 2226: 2217: 2143: 2134: 2047: 2035: 2026: 2014: 2008: 2005: 1996: 1993: 1987: 1978: 1958: 1946: 1937: 1925: 1887: 1878: 1535: 1526: 1450: 1432: 1403: 1394: 1365: 1362: 1174: 1162: 1153: 1141: 1135: 1132: 1123: 1120: 1114: 1105: 1085: 1073: 1064: 1052: 1014: 1005: 941: 929: 920: 908: 862: 853: 794: 776: 702: 693: 647: 638: 568: 559: 482: 479: 443: 440: 383: 380: 374: 371: 2621:Positions in impartial games fall into two 287:At any given point in the game, a player's 53:Learn how and when to remove these messages 6694: 6680: 6672: 1281:referenced in our example game are called 6663: 6590: 6400: 6371: 6345: 6325: 6305: 6273: 6272: 6270: 6247: 6224: 6204: 6170: 6150: 6130: 6093: 6059: 6028: 6004: 5998: 5993:was defined to be different from all the 5978: 5951: 5945: 5922: 5901: 5892: 5865: 5859: 5838: 5829: 5806: 5779: 5773: 5752: 5743: 5718: 5694: 5693: 5691: 5663: 5638: 5614: 5583: 5555: 5532: 5508: 5507: 5505: 5471: 5448: 5423: 5386: 5365: 5364: 5362: 5328: 5294: 5273: 5272: 5270: 5239: 5218: 5217: 5215: 5190: 5165: 5144: 5135: 5115: 5094: 5088: 5057: 5037: 5006: 4982: 4976: 4964:{\displaystyle n_{1},n_{2},\ldots ,n_{k}} 4955: 4936: 4923: 4917: 4893: 4864: 4840: 4818: 4802: 4779: 4758: 4742: 4736: 4708: 4689: 4676: 4661: 4615: 4595: 4567: 4509: 4467: 4446: 4445: 4443: 4411: 4362: 4330: 4309: 4308: 4306: 4269: 4246: 4225: 4224: 4222: 4196: 4170: 4135: 4104: 4078: 4047: 4023: 4022: 4020: 3989: 3958: 3921: 3900: 3899: 3897: 3865: 3844: 3843: 3841: 3821: 3795: 3774: 3773: 3771: 3750: 3749: 3747: 3715: 3694: 3693: 3691: 3665: 3641: 3640: 3638: 3606: 3580: 3554: 3533: 3532: 3530: 3510: 3490: 3470: 3438: 3417: 3416: 3414: 3388: 3365: 3333: 3307: 3275: 3255: 3234: 3233: 3231: 3211: 3166: 3145: 3144: 3142: 3105: 3084: 3083: 3081: 3056: 3055: 3053: 3026: 3004: 2983: 2982: 2980: 2938: 2912: 2889: 2858: 2838: 2807: 2787: 2763: 2762: 2760: 2737: 2716: 2715: 2713: 2690: 2664: 2663: 2661: 2635: 2634: 2632: 2507: 2464: 2463: 2241: 2240: 2231: 2230: 2202: 2201: 2178: 2147: 2146: 2128: 2127: 2113: 2086: 2058: 2057: 2051: 2050: 1972: 1971: 1962: 1961: 1910: 1909: 1900: 1899: 1863: 1862: 1856: 1855: 1846: 1824: 1783: 1758: 1733: 1713: 1693: 1673: 1632: 1607: 1582: 1494: 1468: 1421: 1383: 1360: 1337: 1317: 1294: 1263: 1240: 1217: 1185: 1184: 1178: 1177: 1099: 1098: 1089: 1088: 1037: 1036: 1027: 1026: 990: 989: 983: 982: 980: 954: 953: 902: 901: 899: 875: 874: 838: 837: 835: 812: 774: 747: 724: 691: 668: 636: 613: 586: 557: 530: 500: 477: 438: 348: 328: 308: 183:Learn how and when to remove this message 165:Learn how and when to remove this message 149:, without removing the technical details. 110:Learn how and when to remove this message 6434:Winning Ways for your Mathematical Plays 5001:The first thing we need to note is that 3575:according to their winning strategy for 3485:according to their winning strategy for 2169:To compute the starting position of the 975:Finally, at step 1, Alice's position is 73:This article includes a list of general 6469: 5130:, then the previous player can move to 4042:In the forward direction, suppose that 1668:to get a combined game with six heaps: 6296:of the Grundy values of its summands. 6088:. By transitivity, we conclude that 5083:. If the next player makes a move to 3168: 3006: 2383: 2314: 2260: 2208: 2180: 1826: 147:make it understandable to non-experts 7: 3549:-position), and respond to moves in 2081:, we'll label the starting position 1819:, we'll label its starting position 1541:{\displaystyle *(n+1)=*n\cup \{*n\}} 211:is equivalent to a one-heap game of 6649:Milvang-Jensen, Brit C. A. (2000), 6601:10.17323/1609-4514-2006-6-2-359-388 4767:{\displaystyle G_{i}\approx *n_{i}} 3172: 3111: 2462: 2379: 2366: 2310: 2297: 2256: 2229: 2212: 2197: 2184: 6743:First-player and second-player win 5801:then the previous player moves in 4551:{\displaystyle G'\approx G'+(G+G)} 3107: 2972: 2891: 2656:), or the previous player wins (a 2078: 1848: 769:move would result in the position 284:(a player who cannot move loses). 79:it lacks sufficient corresponding 14: 5032:, by way of the second lemma. If 4399:{\displaystyle G\approx G+(G+G')} 3176: 3115: 3028: 2968: 2370: 2301: 2247: 2216: 2188: 2170: 2115: 2088: 1816: 1665: 392:{\displaystyle (A,B)=(\{\},\{\})} 34:This article has multiple issues. 7761:Theorems in discrete mathematics 6850:Coalition-proof Nash equilibrium 6482:"Über mathematische Kampfspiele" 5210:. After this, the position is a 4264:In the reverse direction, since 3953:As a further step, we show that 3860:-position. Thus, in this case, 2933:is in the same outcome class as 126: 64: 23: 5887:, the previous player moves in 3360:share an outcome class for all 42:or discuss these issues on the 6860:Evolutionarily stable strategy 6366:has the same Grundy value as 6282:{\displaystyle {\mathcal {P}}} 5703:{\displaystyle {\mathcal {P}}} 5517:{\displaystyle {\mathcal {P}}} 5374:{\displaystyle {\mathcal {P}}} 5282:{\displaystyle {\mathcal {P}}} 5227:{\displaystyle {\mathcal {P}}} 4545: 4533: 4497:{\displaystyle G'\approx G'+B} 4455:{\displaystyle {\mathcal {P}}} 4393: 4376: 4318:{\displaystyle {\mathcal {P}}} 4234:{\displaystyle {\mathcal {P}}} 4032:{\displaystyle {\mathcal {P}}} 3909:{\displaystyle {\mathcal {N}}} 3853:{\displaystyle {\mathcal {P}}} 3783:{\displaystyle {\mathcal {P}}} 3759:{\displaystyle {\mathcal {N}}} 3703:{\displaystyle {\mathcal {N}}} 3650:{\displaystyle {\mathcal {P}}} 3542:{\displaystyle {\mathcal {P}}} 3426:{\displaystyle {\mathcal {P}}} 3243:{\displaystyle {\mathcal {P}}} 3154:{\displaystyle {\mathcal {P}}} 3093:{\displaystyle {\mathcal {N}}} 3065:{\displaystyle {\mathcal {N}}} 3041:{\displaystyle \color {red}S'} 3014:{\displaystyle \color {blue}S} 2992:{\displaystyle {\mathcal {P}}} 2772:{\displaystyle {\mathcal {N}}} 2725:{\displaystyle {\mathcal {P}}} 2101:{\displaystyle \color {red}S'} 1834:{\displaystyle \color {blue}S} 1810: 1659: 1511: 1499: 466: 386: 368: 362: 350: 1: 6788:Simultaneous action selection 6458:Indistinguishability quotient 1571:Two games can be combined by 7720:List of games in game theory 6900:Quantal response equilibrium 6890:Perfect Bayesian equilibrium 6825:Bayes correlated equilibrium 6081:{\displaystyle G'\approx *m} 5408:{\displaystyle G'\approx *m} 4350:{\displaystyle G\approx G+A} 3836:to that position is still a 3295:{\displaystyle G\approx A+G} 2833:if, no matter what position 1456:{\displaystyle *2=\{*0,*1\}} 631:. Thus, Bob's position is 201:Sprague–Grundy theorem 7189:Optional prisoner's dilemma 6920:Self-confirming equilibrium 6579:Moscow Mathematical Journal 6487:Tohoku Mathematical Journal 6187:{\displaystyle G\approx *m} 6110:{\displaystyle G\approx *m} 6047:{\displaystyle G\approx G'} 5500:is the null set, clearly a 5313:{\displaystyle G\approx G'} 5025:{\displaystyle G\approx G'} 4881:{\displaystyle G\approx *m} 4634:{\displaystyle G\approx G'} 4066:{\displaystyle G\approx G'} 3977:{\displaystyle G\approx G'} 3505:(which exists by virtue of 2877:{\displaystyle G\approx G'} 1664:We can combine it with our 7779: 7654:Principal variation search 7370:Aumann's agreement theorem 7033:Strategy-stealing argument 6945:Trembling hand equilibrium 6875:Markov perfect equilibrium 6870:Mertens-stable equilibrium 5880:{\displaystyle n_{i}>m} 5794:{\displaystyle n_{i}<m} 1289:. In general, the nimber 7756:Combinatorial game theory 7690:Combinatorial game theory 7349:Princess and monster game 6905:Quasi-perfect equilibrium 6830:Bayesian Nash equilibrium 6417:combinatorial game theory 3790:-position from among the 2900:{\displaystyle \forall H} 1409:{\displaystyle *1=\{*0\}} 807:. We call this position 800:{\displaystyle \{*0,*1\}} 581:. We name this position 197:combinatorial game theory 7705:Evolutionary game theory 7438:Antoine Augustin Cournot 7324:Guess 2/3 of the average 7121:Strictly determined game 6915:Satisfaction equilibrium 6733:Escalation of commitment 4603:{\displaystyle \approx } 4575:{\displaystyle \approx } 1555:ber comes from the game 7710:Glossary of game theory 7309:Stackelberg competition 6935:Strong Nash equilibrium 6526:"Mathematics and games" 5966:{\displaystyle n_{i}=m} 5602:{\displaystyle m'<m} 4910:mex (minimum exclusion) 4610:, we can conclude that 3076:is the player with the 1482:{\displaystyle n\geq 0} 525:leaves Bob in position 94:more precise citations. 7735:Tragedy of the commons 7715:List of game theorists 7695:Confrontation analysis 7405:Sprague–Grundy theorem 6925:Sequential equilibrium 6845:Correlated equilibrium 6409: 6389: 6360: 6334: 6320:has a Grundy value of 6314: 6283: 6256: 6236: 6219:(i.e. of the position 6213: 6188: 6159: 6139: 6111: 6082: 6048: 6014: 5987: 5967: 5934: 5911: 5910:{\displaystyle *n_{i}} 5881: 5848: 5847:{\displaystyle *n_{i}} 5818: 5795: 5762: 5761:{\displaystyle *n_{i}} 5732: 5704: 5680: 5652: 5623: 5603: 5572: 5544: 5518: 5494: 5460: 5437: 5409: 5375: 5351: 5314: 5283: 5259: 5228: 5204: 5179: 5154: 5153:{\displaystyle *n_{i}} 5124: 5104: 5077: 5046: 5026: 4992: 4965: 4902: 4882: 4853: 4768: 4721: 4635: 4604: 4576: 4552: 4498: 4456: 4432: 4400: 4351: 4319: 4295: 4294:{\displaystyle A=G+G'} 4255: 4235: 4211: 4185: 4155: 4124: 4093: 4067: 4033: 4009: 3978: 3936: 3910: 3886: 3854: 3830: 3810: 3784: 3760: 3736: 3704: 3680: 3660:On the other hand, if 3651: 3627: 3595: 3569: 3543: 3519: 3499: 3479: 3465:: respond to moves in 3459: 3427: 3403: 3374: 3354: 3322: 3296: 3264: 3244: 3220: 3192: 3155: 3131: 3094: 3066: 3042: 3015: 2999:-position. Thus, both 2993: 2958: 2927: 2901: 2878: 2847: 2821: 2796: 2773: 2749: 2726: 2702: 2674: 2645: 2607: 2494: 2161: 2102: 2069: 1835: 1797: 1772: 1747: 1722: 1702: 1682: 1646: 1621: 1596: 1542: 1483: 1457: 1410: 1372: 1349: 1326: 1306: 1275: 1252: 1229: 1198: 967: 885: 824: 801: 759: 736: 709: 708:{\displaystyle \{*1\}} 680: 654: 653:{\displaystyle \{*1\}} 625: 598: 575: 574:{\displaystyle \{*0\}} 542: 512: 489: 450: 433:can simply be written 393: 337: 317: 209:normal play convention 7508:Jean-François Mertens 6538:: 6–8. Archived from 6410: 6390: 6361: 6335: 6315: 6284: 6257: 6237: 6214: 6189: 6160: 6140: 6112: 6083: 6049: 6015: 6013:{\displaystyle n_{i}} 5988: 5968: 5935: 5912: 5882: 5849: 5819: 5796: 5763: 5733: 5705: 5681: 5653: 5624: 5604: 5573: 5545: 5519: 5495: 5493:{\displaystyle G'+*m} 5461: 5438: 5410: 5376: 5352: 5350:{\displaystyle G'+*m} 5323:Now let us show that 5315: 5284: 5260: 5229: 5205: 5180: 5155: 5125: 5105: 5103:{\displaystyle G_{i}} 5078: 5047: 5027: 4993: 4991:{\displaystyle n_{i}} 4966: 4903: 4883: 4859:. We will show that 4854: 4769: 4722: 4636: 4605: 4577: 4553: 4499: 4457: 4433: 4431:{\displaystyle B=G+G} 4406:. Similarly, since 4401: 4352: 4320: 4296: 4256: 4236: 4212: 4186: 4156: 4125: 4094: 4068: 4034: 4010: 3979: 3937: 3916:-position, just like 3911: 3887: 3885:{\displaystyle A+G+H} 3855: 3831: 3811: 3785: 3761: 3737: 3735:{\displaystyle A+G+H} 3705: 3681: 3652: 3628: 3626:{\displaystyle A+G+H} 3596: 3570: 3544: 3520: 3500: 3480: 3460: 3458:{\displaystyle A+G+H} 3428: 3404: 3375: 3355: 3353:{\displaystyle A+G+H} 3323: 3297: 3265: 3245: 3221: 3193: 3156: 3132: 3100:-positions. In fact, 3095: 3067: 3043: 3016: 2994: 2959: 2928: 2902: 2879: 2848: 2822: 2797: 2774: 2750: 2727: 2703: 2685:). So, for example, 2675: 2646: 2608: 2495: 2162: 2103: 2070: 1841:, and color it blue: 1836: 1798: 1773: 1748: 1723: 1703: 1683: 1647: 1622: 1597: 1543: 1484: 1458: 1411: 1373: 1350: 1327: 1307: 1276: 1253: 1230: 1199: 968: 886: 825: 802: 760: 737: 710: 681: 655: 626: 599: 576: 543: 513: 490: 451: 394: 338: 318: 282:normal play condition 7637:Search optimizations 7513:Jennifer Tour Chayes 7400:Revelation principle 7395:Purification theorem 7334:Nash bargaining game 7299:Bertrand competition 7284:El Farol Bar problem 7249:Electronic mail game 7214:Lewis signaling game 6758:Hierarchy of beliefs 6440:On Numbers and Games 6399: 6388:{\displaystyle *m+H} 6370: 6344: 6324: 6304: 6269: 6246: 6223: 6203: 6169: 6149: 6129: 6092: 6058: 6027: 6023:In summary, we have 5997: 5977: 5944: 5921: 5891: 5858: 5828: 5805: 5772: 5742: 5717: 5690: 5662: 5637: 5613: 5582: 5554: 5531: 5504: 5470: 5447: 5422: 5385: 5361: 5327: 5293: 5269: 5258:{\displaystyle G+G'} 5238: 5214: 5189: 5164: 5134: 5114: 5087: 5076:{\displaystyle G+G'} 5056: 5036: 5005: 4975: 4916: 4892: 4863: 4778: 4735: 4729:induction hypothesis 4660: 4656:Consider a position 4651:structural induction 4614: 4594: 4584:equivalence relation 4566: 4508: 4466: 4442: 4410: 4361: 4329: 4305: 4268: 4245: 4221: 4195: 4169: 4154:{\displaystyle G+G'} 4134: 4123:{\displaystyle G'+G} 4103: 4077: 4046: 4019: 4008:{\displaystyle G+G'} 3988: 3957: 3920: 3896: 3864: 3840: 3820: 3794: 3770: 3746: 3714: 3690: 3664: 3637: 3605: 3579: 3553: 3529: 3509: 3489: 3469: 3437: 3413: 3387: 3364: 3332: 3306: 3274: 3254: 3230: 3210: 3165: 3141: 3104: 3080: 3052: 3025: 3003: 2979: 2957:{\displaystyle G'+H} 2937: 2911: 2888: 2857: 2837: 2806: 2786: 2759: 2736: 2712: 2689: 2660: 2631: 2506: 2177: 2112: 2085: 1845: 1823: 1782: 1757: 1732: 1712: 1692: 1672: 1631: 1606: 1581: 1493: 1467: 1420: 1382: 1371:{\displaystyle \{\}} 1359: 1336: 1316: 1293: 1262: 1239: 1216: 979: 898: 834: 811: 773: 746: 723: 719:moves would then be 690: 667: 635: 612: 585: 556: 529: 499: 488:{\displaystyle \{\}} 476: 449:{\displaystyle \{\}} 437: 347: 327: 307: 7685:Bounded rationality 7304:Cournot competition 7254:Rock paper scissors 7229:Battle of the sexes 7219:Volunteer's dilemma 7091:Perfect information 7018:Dominant strategies 6855:Epsilon-equilibrium 6738:Extensive-form game 6359:{\displaystyle G+H} 5679:{\displaystyle *m'} 5571:{\displaystyle *m'} 4210:{\displaystyle G+G} 4184:{\displaystyle G+G} 4130:(which is equal to 4092:{\displaystyle H=G} 3935:{\displaystyle G+H} 3809:{\displaystyle G+H} 3679:{\displaystyle G+H} 3594:{\displaystyle G+H} 3568:{\displaystyle G+H} 3402:{\displaystyle G+H} 3321:{\displaystyle G+H} 2926:{\displaystyle G+H} 2079:second example game 274:perfect information 7664:Paranoid algorithm 7644:Alpha–beta pruning 7523:John Maynard Smith 7354:Rendezvous problem 7194:Traveler's dilemma 7184:Gift-exchange game 7179:Prisoner's dilemma 7096:Large Poisson game 7063:Bargaining problem 6968:Backward induction 6940:Subgame perfection 6895:Proper equilibrium 6429:John Horton Conway 6405: 6385: 6356: 6330: 6310: 6279: 6252: 6235:{\displaystyle *m} 6232: 6209: 6184: 6155: 6135: 6107: 6078: 6044: 6010: 5983: 5963: 5933:{\displaystyle *m} 5930: 5907: 5877: 5844: 5817:{\displaystyle *m} 5814: 5791: 5758: 5731:{\displaystyle G'} 5728: 5700: 5676: 5651:{\displaystyle G'} 5648: 5619: 5599: 5568: 5543:{\displaystyle *m} 5540: 5514: 5490: 5459:{\displaystyle *m} 5456: 5436:{\displaystyle G'} 5433: 5405: 5371: 5347: 5310: 5279: 5255: 5224: 5203:{\displaystyle G'} 5200: 5178:{\displaystyle G'} 5175: 5150: 5120: 5100: 5073: 5042: 5022: 4988: 4961: 4898: 4878: 4849: 4764: 4717: 4631: 4600: 4572: 4548: 4494: 4452: 4428: 4396: 4347: 4315: 4291: 4251: 4231: 4207: 4181: 4151: 4120: 4089: 4063: 4029: 4005: 3974: 3932: 3906: 3882: 3850: 3826: 3806: 3780: 3756: 3732: 3700: 3676: 3647: 3623: 3591: 3565: 3539: 3515: 3495: 3475: 3455: 3423: 3399: 3370: 3350: 3318: 3292: 3270:, the equivalence 3260: 3240: 3216: 3188: 3187: 3186: 3185: 3151: 3127: 3126: 3125: 3124: 3090: 3062: 3038: 3037: 3011: 3010: 2989: 2954: 2923: 2897: 2874: 2843: 2820:{\displaystyle G'} 2817: 2792: 2769: 2748:{\displaystyle *1} 2745: 2722: 2701:{\displaystyle *0} 2698: 2670: 2641: 2603: 2490: 2489: 2488: 2487: 2486: 2485: 2484: 2483: 2482: 2481: 2480: 2479: 2478: 2477: 2476: 2475: 2474: 2473: 2472: 2471: 2470: 2157: 2156: 2108:and color it red: 2098: 2097: 2065: 2064: 1831: 1830: 1817:first example game 1796:{\displaystyle C'} 1793: 1771:{\displaystyle B'} 1768: 1746:{\displaystyle A'} 1743: 1718: 1698: 1678: 1645:{\displaystyle C'} 1642: 1620:{\displaystyle B'} 1617: 1595:{\displaystyle A'} 1592: 1538: 1479: 1453: 1406: 1368: 1348:{\displaystyle *0} 1345: 1322: 1305:{\displaystyle *n} 1302: 1274:{\displaystyle *2} 1271: 1251:{\displaystyle *1} 1248: 1228:{\displaystyle *0} 1225: 1212:The special names 1194: 963: 881: 823:{\displaystyle *2} 820: 797: 758:{\displaystyle *1} 755: 735:{\displaystyle *0} 732: 705: 679:{\displaystyle *1} 676: 650: 624:{\displaystyle *1} 621: 597:{\displaystyle *1} 594: 571: 541:{\displaystyle *0} 538: 511:{\displaystyle *0} 508: 485: 446: 389: 333: 313: 203:states that every 7743: 7742: 7649:Aspiration window 7618:Suzanne Scotchmer 7573:Oskar Morgenstern 7468:Donald B. Gillies 7410:Zermelo's theorem 7339:Induction puzzles 7294:Fair cake-cutting 7269:Public goods game 7199:Coordination game 7073:Intransitive game 7003:Forward induction 6885:Pareto efficiency 6865:Gibbs equilibrium 6835:Berge equilibrium 6783:Simultaneous game 6544:Reprinted, 1964, 6408:{\displaystyle H} 6333:{\displaystyle m} 6313:{\displaystyle G} 6255:{\displaystyle m} 6212:{\displaystyle m} 6158:{\displaystyle m} 6138:{\displaystyle G} 5986:{\displaystyle m} 5622:{\displaystyle m} 5466:are empty. Then 5123:{\displaystyle G} 5045:{\displaystyle k} 4901:{\displaystyle m} 4254:{\displaystyle G} 3829:{\displaystyle A} 3518:{\displaystyle A} 3498:{\displaystyle A} 3478:{\displaystyle A} 3373:{\displaystyle H} 3263:{\displaystyle A} 3219:{\displaystyle G} 2846:{\displaystyle H} 2795:{\displaystyle G} 2732:-position, while 1721:{\displaystyle C} 1701:{\displaystyle B} 1681:{\displaystyle A} 1325:{\displaystyle n} 336:{\displaystyle B} 316:{\displaystyle A} 193: 192: 185: 175: 174: 167: 120: 119: 112: 57: 7768: 7730:Topological game 7725:No-win situation 7623:Thomas Schelling 7603:Robert B. Wilson 7563:Merrill M. Flood 7533:John von Neumann 7443:Ariel Rubinstein 7428:Albert W. Tucker 7279:War of attrition 7239:Matching pennies 6880:Nash equilibrium 6803:Mechanism design 6768:Normal-form game 6723:Cooperative game 6696: 6689: 6682: 6673: 6668: 6667: 6657: 6613: 6612: 6594: 6574: 6568: 6567: 6555: 6549: 6543: 6518: 6512: 6511: 6474: 6414: 6412: 6411: 6406: 6394: 6392: 6391: 6386: 6365: 6363: 6362: 6357: 6339: 6337: 6336: 6331: 6319: 6317: 6316: 6311: 6288: 6286: 6285: 6280: 6278: 6277: 6261: 6259: 6258: 6253: 6241: 6239: 6238: 6233: 6218: 6216: 6215: 6210: 6193: 6191: 6190: 6185: 6164: 6162: 6161: 6156: 6144: 6142: 6141: 6136: 6116: 6114: 6113: 6108: 6087: 6085: 6084: 6079: 6068: 6053: 6051: 6050: 6045: 6043: 6019: 6017: 6016: 6011: 6009: 6008: 5992: 5990: 5989: 5984: 5972: 5970: 5969: 5964: 5956: 5955: 5939: 5937: 5936: 5931: 5916: 5914: 5913: 5908: 5906: 5905: 5886: 5884: 5883: 5878: 5870: 5869: 5854:; otherwise, if 5853: 5851: 5850: 5845: 5843: 5842: 5823: 5821: 5820: 5815: 5800: 5798: 5797: 5792: 5784: 5783: 5767: 5765: 5764: 5759: 5757: 5756: 5737: 5735: 5734: 5729: 5727: 5709: 5707: 5706: 5701: 5699: 5698: 5685: 5683: 5682: 5677: 5675: 5657: 5655: 5654: 5649: 5647: 5628: 5626: 5625: 5620: 5608: 5606: 5605: 5600: 5592: 5577: 5575: 5574: 5569: 5567: 5549: 5547: 5546: 5541: 5523: 5521: 5520: 5515: 5513: 5512: 5499: 5497: 5496: 5491: 5480: 5465: 5463: 5462: 5457: 5442: 5440: 5439: 5434: 5432: 5414: 5412: 5411: 5406: 5395: 5380: 5378: 5377: 5372: 5370: 5369: 5356: 5354: 5353: 5348: 5337: 5319: 5317: 5316: 5311: 5309: 5288: 5286: 5285: 5280: 5278: 5277: 5264: 5262: 5261: 5256: 5254: 5233: 5231: 5230: 5225: 5223: 5222: 5209: 5207: 5206: 5201: 5199: 5184: 5182: 5181: 5176: 5174: 5159: 5157: 5156: 5151: 5149: 5148: 5129: 5127: 5126: 5121: 5109: 5107: 5106: 5101: 5099: 5098: 5082: 5080: 5079: 5074: 5072: 5051: 5049: 5048: 5043: 5031: 5029: 5028: 5023: 5021: 4997: 4995: 4994: 4989: 4987: 4986: 4970: 4968: 4967: 4962: 4960: 4959: 4941: 4940: 4928: 4927: 4907: 4905: 4904: 4899: 4887: 4885: 4884: 4879: 4858: 4856: 4855: 4850: 4845: 4844: 4823: 4822: 4807: 4806: 4788: 4773: 4771: 4770: 4765: 4763: 4762: 4747: 4746: 4726: 4724: 4723: 4718: 4713: 4712: 4694: 4693: 4681: 4680: 4640: 4638: 4637: 4632: 4630: 4609: 4607: 4606: 4601: 4581: 4579: 4578: 4573: 4557: 4555: 4554: 4549: 4529: 4518: 4503: 4501: 4500: 4495: 4487: 4476: 4461: 4459: 4458: 4453: 4451: 4450: 4437: 4435: 4434: 4429: 4405: 4403: 4402: 4397: 4392: 4356: 4354: 4353: 4348: 4324: 4322: 4321: 4316: 4314: 4313: 4300: 4298: 4297: 4292: 4290: 4260: 4258: 4257: 4252: 4240: 4238: 4237: 4232: 4230: 4229: 4216: 4214: 4213: 4208: 4190: 4188: 4187: 4182: 4160: 4158: 4157: 4152: 4150: 4129: 4127: 4126: 4121: 4113: 4098: 4096: 4095: 4090: 4072: 4070: 4069: 4064: 4062: 4038: 4036: 4035: 4030: 4028: 4027: 4014: 4012: 4011: 4006: 4004: 3983: 3981: 3980: 3975: 3973: 3941: 3939: 3938: 3933: 3915: 3913: 3912: 3907: 3905: 3904: 3891: 3889: 3888: 3883: 3859: 3857: 3856: 3851: 3849: 3848: 3835: 3833: 3832: 3827: 3815: 3813: 3812: 3807: 3789: 3787: 3786: 3781: 3779: 3778: 3765: 3763: 3762: 3757: 3755: 3754: 3741: 3739: 3738: 3733: 3710:-position, then 3709: 3707: 3706: 3701: 3699: 3698: 3685: 3683: 3682: 3677: 3656: 3654: 3653: 3648: 3646: 3645: 3632: 3630: 3629: 3624: 3600: 3598: 3597: 3592: 3574: 3572: 3571: 3566: 3548: 3546: 3545: 3540: 3538: 3537: 3524: 3522: 3521: 3516: 3504: 3502: 3501: 3496: 3484: 3482: 3481: 3476: 3464: 3462: 3461: 3456: 3432: 3430: 3429: 3424: 3422: 3421: 3408: 3406: 3405: 3400: 3379: 3377: 3376: 3371: 3359: 3357: 3356: 3351: 3327: 3325: 3324: 3319: 3301: 3299: 3298: 3293: 3269: 3267: 3266: 3261: 3249: 3247: 3246: 3241: 3239: 3238: 3225: 3223: 3222: 3217: 3197: 3195: 3194: 3189: 3184: 3160: 3158: 3157: 3152: 3150: 3149: 3136: 3134: 3133: 3128: 3123: 3099: 3097: 3096: 3091: 3089: 3088: 3071: 3069: 3068: 3063: 3061: 3060: 3047: 3045: 3044: 3039: 3036: 3020: 3018: 3017: 3012: 2998: 2996: 2995: 2990: 2988: 2987: 2963: 2961: 2960: 2955: 2947: 2932: 2930: 2929: 2924: 2906: 2904: 2903: 2898: 2883: 2881: 2880: 2875: 2873: 2852: 2850: 2849: 2844: 2826: 2824: 2823: 2818: 2816: 2801: 2799: 2798: 2793: 2778: 2776: 2775: 2770: 2768: 2767: 2754: 2752: 2751: 2746: 2731: 2729: 2728: 2723: 2721: 2720: 2707: 2705: 2704: 2699: 2679: 2677: 2676: 2671: 2669: 2668: 2650: 2648: 2647: 2642: 2640: 2639: 2612: 2610: 2609: 2604: 2587: 2564: 2553: 2542: 2522: 2499: 2497: 2496: 2491: 2469: 2468: 2378: 2309: 2255: 2246: 2245: 2236: 2235: 2207: 2206: 2196: 2166: 2164: 2163: 2158: 2152: 2151: 2133: 2132: 2123: 2107: 2105: 2104: 2099: 2096: 2074: 2072: 2071: 2066: 2063: 2062: 2056: 2055: 1977: 1976: 1967: 1966: 1915: 1914: 1905: 1904: 1868: 1867: 1861: 1860: 1840: 1838: 1837: 1832: 1802: 1800: 1799: 1794: 1792: 1777: 1775: 1774: 1769: 1767: 1752: 1750: 1749: 1744: 1742: 1727: 1725: 1724: 1719: 1707: 1705: 1704: 1699: 1687: 1685: 1684: 1679: 1651: 1649: 1648: 1643: 1641: 1626: 1624: 1623: 1618: 1616: 1601: 1599: 1598: 1593: 1591: 1547: 1545: 1544: 1539: 1488: 1486: 1485: 1480: 1462: 1460: 1459: 1454: 1415: 1413: 1412: 1407: 1377: 1375: 1374: 1369: 1354: 1352: 1351: 1346: 1331: 1329: 1328: 1323: 1311: 1309: 1308: 1303: 1280: 1278: 1277: 1272: 1257: 1255: 1254: 1249: 1234: 1232: 1231: 1226: 1203: 1201: 1200: 1195: 1190: 1189: 1183: 1182: 1104: 1103: 1094: 1093: 1042: 1041: 1032: 1031: 995: 994: 988: 987: 972: 970: 969: 964: 959: 958: 907: 906: 890: 888: 887: 882: 880: 879: 843: 842: 829: 827: 826: 821: 806: 804: 803: 798: 764: 762: 761: 756: 741: 739: 738: 733: 714: 712: 711: 706: 685: 683: 682: 677: 659: 657: 656: 651: 630: 628: 627: 622: 603: 601: 600: 595: 580: 578: 577: 572: 547: 545: 544: 539: 517: 515: 514: 509: 494: 492: 491: 486: 463:Example Nim Game 455: 453: 452: 447: 398: 396: 395: 390: 342: 340: 339: 334: 323:(for Alice) and 322: 320: 319: 314: 278:ending condition 268:is a two-player 188: 181: 170: 163: 159: 156: 150: 130: 129: 122: 115: 108: 104: 101: 95: 90:this article by 81:inline citations 68: 67: 60: 49: 27: 26: 19: 7778: 7777: 7771: 7770: 7769: 7767: 7766: 7765: 7746: 7745: 7744: 7739: 7673: 7659:max^n algorithm 7632: 7628:William Vickrey 7588:Reinhard Selten 7543:Kenneth Binmore 7458:David K. Levine 7453:Daniel Kahneman 7420: 7414: 7390:Negamax theorem 7380:Minimax theorem 7358: 7319:Diner's dilemma 7174:All-pay auction 7140: 7126:Stochastic game 7078:Mean-field game 7049: 7042: 7013:Markov strategy 6949: 6815: 6807: 6778:Sequential game 6763:Information set 6748:Game complexity 6718:Congestion game 6706: 6700: 6655: 6648: 6640:The Game of Nim 6622: 6617: 6616: 6592:math.CO/0410026 6576: 6575: 6571: 6557: 6556: 6552: 6520: 6519: 6515: 6476: 6475: 6471: 6466: 6449: 6425:Elwyn Berlekamp 6397: 6396: 6368: 6367: 6342: 6341: 6322: 6321: 6302: 6301: 6267: 6266: 6244: 6243: 6221: 6220: 6201: 6200: 6167: 6166: 6147: 6146: 6127: 6126: 6123: 6090: 6089: 6061: 6056: 6055: 6036: 6025: 6024: 6000: 5995: 5994: 5975: 5974: 5947: 5942: 5941: 5919: 5918: 5897: 5889: 5888: 5861: 5856: 5855: 5834: 5826: 5825: 5803: 5802: 5775: 5770: 5769: 5748: 5740: 5739: 5720: 5715: 5714: 5688: 5687: 5668: 5660: 5659: 5640: 5635: 5634: 5611: 5610: 5585: 5580: 5579: 5560: 5552: 5551: 5529: 5528: 5502: 5501: 5473: 5468: 5467: 5445: 5444: 5425: 5420: 5419: 5388: 5383: 5382: 5359: 5358: 5330: 5325: 5324: 5302: 5291: 5290: 5267: 5266: 5247: 5236: 5235: 5212: 5211: 5192: 5187: 5186: 5167: 5162: 5161: 5140: 5132: 5131: 5112: 5111: 5090: 5085: 5084: 5065: 5054: 5053: 5034: 5033: 5014: 5003: 5002: 4978: 4973: 4972: 4951: 4932: 4919: 4914: 4913: 4912:of the numbers 4890: 4889: 4861: 4860: 4836: 4814: 4798: 4781: 4776: 4775: 4754: 4738: 4733: 4732: 4704: 4685: 4672: 4658: 4657: 4647: 4623: 4612: 4611: 4592: 4591: 4564: 4563: 4522: 4511: 4506: 4505: 4480: 4469: 4464: 4463: 4440: 4439: 4408: 4407: 4385: 4359: 4358: 4327: 4326: 4303: 4302: 4283: 4266: 4265: 4243: 4242: 4219: 4218: 4193: 4192: 4167: 4166: 4143: 4132: 4131: 4106: 4101: 4100: 4099:, we find that 4075: 4074: 4055: 4044: 4043: 4017: 4016: 3997: 3986: 3985: 3984:if and only if 3966: 3955: 3954: 3951: 3918: 3917: 3894: 3893: 3862: 3861: 3838: 3837: 3818: 3817: 3792: 3791: 3768: 3767: 3744: 3743: 3712: 3711: 3688: 3687: 3662: 3661: 3635: 3634: 3633:must also be a 3603: 3602: 3577: 3576: 3551: 3550: 3527: 3526: 3507: 3506: 3487: 3486: 3467: 3466: 3435: 3434: 3411: 3410: 3385: 3384: 3362: 3361: 3330: 3329: 3304: 3303: 3272: 3271: 3252: 3251: 3228: 3227: 3208: 3207: 3204: 3177: 3163: 3162: 3139: 3138: 3116: 3102: 3101: 3078: 3077: 3050: 3049: 3029: 3023: 3022: 3001: 3000: 2977: 2976: 2940: 2935: 2934: 2909: 2908: 2886: 2885: 2884:if and only if 2866: 2855: 2854: 2835: 2834: 2809: 2804: 2803: 2784: 2783: 2757: 2756: 2734: 2733: 2710: 2709: 2687: 2686: 2658: 2657: 2629: 2628: 2624:outcome classes 2619: 2580: 2557: 2546: 2535: 2515: 2504: 2503: 2371: 2302: 2248: 2189: 2175: 2174: 2116: 2110: 2109: 2089: 2083: 2082: 1843: 1842: 1821: 1820: 1813: 1809: 1785: 1780: 1779: 1760: 1755: 1754: 1735: 1730: 1729: 1710: 1709: 1690: 1689: 1670: 1669: 1662: 1658: 1634: 1629: 1628: 1609: 1604: 1603: 1584: 1579: 1578: 1569: 1567:Combining Games 1551:While the word 1491: 1490: 1465: 1464: 1418: 1417: 1380: 1379: 1357: 1356: 1334: 1333: 1314: 1313: 1291: 1290: 1260: 1259: 1237: 1236: 1214: 1213: 1210: 977: 976: 896: 895: 832: 831: 809: 808: 771: 770: 744: 743: 721: 720: 688: 687: 665: 664: 633: 632: 610: 609: 583: 582: 554: 553: 527: 526: 497: 496: 474: 473: 469: 465: 435: 434: 345: 344: 325: 324: 305: 304: 276:satisfying the 270:sequential game 260: 189: 178: 177: 176: 171: 160: 154: 151: 143:help improve it 140: 131: 127: 116: 105: 99: 96: 86:Please help to 85: 69: 65: 28: 24: 17: 12: 11: 5: 7776: 7775: 7772: 7764: 7763: 7758: 7748: 7747: 7741: 7740: 7738: 7737: 7732: 7727: 7722: 7717: 7712: 7707: 7702: 7697: 7692: 7687: 7681: 7679: 7675: 7674: 7672: 7671: 7666: 7661: 7656: 7651: 7646: 7640: 7638: 7634: 7633: 7631: 7630: 7625: 7620: 7615: 7610: 7605: 7600: 7595: 7593:Robert Axelrod 7590: 7585: 7580: 7575: 7570: 7568:Olga Bondareva 7565: 7560: 7558:Melvin Dresher 7555: 7550: 7548:Leonid Hurwicz 7545: 7540: 7535: 7530: 7525: 7520: 7515: 7510: 7505: 7500: 7495: 7490: 7485: 7483:Harold W. Kuhn 7480: 7475: 7473:Drew Fudenberg 7470: 7465: 7463:David M. Kreps 7460: 7455: 7450: 7448:Claude Shannon 7445: 7440: 7435: 7430: 7424: 7422: 7416: 7415: 7413: 7412: 7407: 7402: 7397: 7392: 7387: 7385:Nash's theorem 7382: 7377: 7372: 7366: 7364: 7360: 7359: 7357: 7356: 7351: 7346: 7341: 7336: 7331: 7326: 7321: 7316: 7311: 7306: 7301: 7296: 7291: 7286: 7281: 7276: 7271: 7266: 7261: 7256: 7251: 7246: 7244:Ultimatum game 7241: 7236: 7231: 7226: 7224:Dollar auction 7221: 7216: 7211: 7209:Centipede game 7206: 7201: 7196: 7191: 7186: 7181: 7176: 7171: 7166: 7164:Infinite chess 7161: 7156: 7150: 7148: 7142: 7141: 7139: 7138: 7133: 7131:Symmetric game 7128: 7123: 7118: 7116:Signaling game 7113: 7111:Screening game 7108: 7103: 7101:Potential game 7098: 7093: 7088: 7080: 7075: 7070: 7065: 7060: 7054: 7052: 7044: 7043: 7041: 7040: 7035: 7030: 7028:Mixed strategy 7025: 7020: 7015: 7010: 7005: 7000: 6995: 6990: 6985: 6980: 6975: 6970: 6965: 6959: 6957: 6951: 6950: 6948: 6947: 6942: 6937: 6932: 6927: 6922: 6917: 6912: 6910:Risk dominance 6907: 6902: 6897: 6892: 6887: 6882: 6877: 6872: 6867: 6862: 6857: 6852: 6847: 6842: 6837: 6832: 6827: 6821: 6819: 6809: 6808: 6806: 6805: 6800: 6795: 6790: 6785: 6780: 6775: 6770: 6765: 6760: 6755: 6753:Graphical game 6750: 6745: 6740: 6735: 6730: 6725: 6720: 6714: 6712: 6708: 6707: 6701: 6699: 6698: 6691: 6684: 6676: 6670: 6669: 6646: 6637: 6632: 6621: 6620:External links 6618: 6615: 6614: 6585:(2): 359–388. 6569: 6550: 6542:on 2007-09-27. 6513: 6478:Sprague, R. P. 6468: 6467: 6465: 6462: 6461: 6460: 6455: 6448: 6445: 6404: 6384: 6381: 6378: 6375: 6355: 6352: 6349: 6329: 6309: 6298: 6297: 6290: 6276: 6263: 6251: 6231: 6228: 6208: 6183: 6180: 6177: 6174: 6154: 6134: 6122: 6119: 6117:, as desired. 6106: 6103: 6100: 6097: 6077: 6074: 6071: 6067: 6064: 6042: 6039: 6035: 6032: 6007: 6003: 5982: 5962: 5959: 5954: 5950: 5929: 5926: 5904: 5900: 5896: 5876: 5873: 5868: 5864: 5841: 5837: 5833: 5813: 5810: 5790: 5787: 5782: 5778: 5755: 5751: 5747: 5738:to the option 5726: 5723: 5697: 5674: 5671: 5667: 5646: 5643: 5618: 5598: 5595: 5591: 5588: 5566: 5563: 5559: 5550:to the option 5539: 5536: 5511: 5489: 5486: 5483: 5479: 5476: 5455: 5452: 5431: 5428: 5404: 5401: 5398: 5394: 5391: 5368: 5346: 5343: 5340: 5336: 5333: 5308: 5305: 5301: 5298: 5276: 5253: 5250: 5246: 5243: 5221: 5198: 5195: 5173: 5170: 5147: 5143: 5139: 5119: 5097: 5093: 5071: 5068: 5064: 5061: 5041: 5020: 5017: 5013: 5010: 4985: 4981: 4958: 4954: 4950: 4947: 4944: 4939: 4935: 4931: 4926: 4922: 4897: 4877: 4874: 4871: 4868: 4848: 4843: 4839: 4835: 4832: 4829: 4826: 4821: 4817: 4813: 4810: 4805: 4801: 4797: 4794: 4791: 4787: 4784: 4761: 4757: 4753: 4750: 4745: 4741: 4716: 4711: 4707: 4703: 4700: 4697: 4692: 4688: 4684: 4679: 4675: 4671: 4668: 4665: 4646: 4643: 4629: 4626: 4622: 4619: 4599: 4571: 4547: 4544: 4541: 4538: 4535: 4532: 4528: 4525: 4521: 4517: 4514: 4493: 4490: 4486: 4483: 4479: 4475: 4472: 4449: 4427: 4424: 4421: 4418: 4415: 4395: 4391: 4388: 4384: 4381: 4378: 4375: 4372: 4369: 4366: 4346: 4343: 4340: 4337: 4334: 4312: 4289: 4286: 4282: 4279: 4276: 4273: 4250: 4228: 4206: 4203: 4200: 4180: 4177: 4174: 4149: 4146: 4142: 4139: 4119: 4116: 4112: 4109: 4088: 4085: 4082: 4061: 4058: 4054: 4051: 4026: 4003: 4000: 3996: 3993: 3972: 3969: 3965: 3962: 3950: 3947: 3931: 3928: 3925: 3903: 3881: 3878: 3875: 3872: 3869: 3847: 3825: 3805: 3802: 3799: 3777: 3753: 3731: 3728: 3725: 3722: 3719: 3697: 3675: 3672: 3669: 3644: 3622: 3619: 3616: 3613: 3610: 3590: 3587: 3584: 3564: 3561: 3558: 3536: 3514: 3494: 3474: 3454: 3451: 3448: 3445: 3442: 3420: 3398: 3395: 3392: 3369: 3349: 3346: 3343: 3340: 3337: 3317: 3314: 3311: 3291: 3288: 3285: 3282: 3279: 3259: 3237: 3215: 3203: 3200: 3183: 3180: 3175: 3171: 3148: 3122: 3119: 3114: 3110: 3087: 3059: 3035: 3032: 3009: 2986: 2953: 2950: 2946: 2943: 2922: 2919: 2916: 2896: 2893: 2872: 2869: 2865: 2862: 2842: 2815: 2812: 2791: 2782:Two positions 2766: 2744: 2741: 2719: 2697: 2694: 2667: 2638: 2618: 2615: 2602: 2599: 2596: 2593: 2590: 2586: 2583: 2579: 2576: 2573: 2570: 2567: 2563: 2560: 2556: 2552: 2549: 2545: 2541: 2538: 2534: 2531: 2528: 2525: 2521: 2518: 2514: 2511: 2467: 2461: 2458: 2455: 2452: 2449: 2446: 2443: 2440: 2437: 2434: 2431: 2428: 2425: 2422: 2419: 2416: 2413: 2410: 2407: 2404: 2401: 2398: 2395: 2392: 2389: 2386: 2382: 2377: 2374: 2369: 2365: 2362: 2359: 2356: 2353: 2350: 2347: 2344: 2341: 2338: 2335: 2332: 2329: 2326: 2323: 2320: 2317: 2313: 2308: 2305: 2300: 2296: 2293: 2290: 2287: 2284: 2281: 2278: 2275: 2272: 2269: 2266: 2263: 2259: 2254: 2251: 2244: 2239: 2234: 2228: 2225: 2222: 2219: 2215: 2211: 2205: 2200: 2195: 2192: 2187: 2183: 2155: 2150: 2145: 2142: 2139: 2136: 2131: 2126: 2122: 2119: 2095: 2092: 2061: 2054: 2049: 2046: 2043: 2040: 2037: 2034: 2031: 2028: 2025: 2022: 2019: 2016: 2013: 2010: 2007: 2004: 2001: 1998: 1995: 1992: 1989: 1986: 1983: 1980: 1975: 1970: 1965: 1960: 1957: 1954: 1951: 1948: 1945: 1942: 1939: 1936: 1933: 1930: 1927: 1924: 1921: 1918: 1913: 1908: 1903: 1898: 1895: 1892: 1889: 1886: 1883: 1880: 1877: 1874: 1871: 1866: 1859: 1854: 1851: 1829: 1808: 1805: 1791: 1788: 1766: 1763: 1741: 1738: 1717: 1697: 1677: 1657: 1656:Example Game 2 1654: 1640: 1637: 1615: 1612: 1590: 1587: 1568: 1565: 1537: 1534: 1531: 1528: 1525: 1522: 1519: 1516: 1513: 1510: 1507: 1504: 1501: 1498: 1478: 1475: 1472: 1452: 1449: 1446: 1443: 1440: 1437: 1434: 1431: 1428: 1425: 1405: 1402: 1399: 1396: 1393: 1390: 1387: 1367: 1364: 1344: 1341: 1321: 1301: 1298: 1270: 1267: 1247: 1244: 1224: 1221: 1209: 1206: 1205: 1204: 1193: 1188: 1181: 1176: 1173: 1170: 1167: 1164: 1161: 1158: 1155: 1152: 1149: 1146: 1143: 1140: 1137: 1134: 1131: 1128: 1125: 1122: 1119: 1116: 1113: 1110: 1107: 1102: 1097: 1092: 1087: 1084: 1081: 1078: 1075: 1072: 1069: 1066: 1063: 1060: 1057: 1054: 1051: 1048: 1045: 1040: 1035: 1030: 1025: 1022: 1019: 1016: 1013: 1010: 1007: 1004: 1001: 998: 993: 986: 973: 962: 957: 952: 949: 946: 943: 940: 937: 934: 931: 928: 925: 922: 919: 916: 913: 910: 905: 892: 878: 873: 870: 867: 864: 861: 858: 855: 852: 849: 846: 841: 819: 816: 796: 793: 790: 787: 784: 781: 778: 754: 751: 731: 728: 704: 701: 698: 695: 675: 672: 661: 649: 646: 643: 640: 620: 617: 605: 593: 590: 570: 567: 564: 561: 537: 534: 519: 507: 504: 484: 481: 464: 461: 445: 442: 406:impartial game 388: 385: 382: 379: 376: 373: 370: 367: 364: 361: 358: 355: 352: 332: 312: 293:is the set of 259: 256: 221:ordinal number 217:natural number 205:impartial game 191: 190: 173: 172: 134: 132: 125: 118: 117: 72: 70: 63: 58: 32: 31: 29: 22: 15: 13: 10: 9: 6: 4: 3: 2: 7774: 7773: 7762: 7759: 7757: 7754: 7753: 7751: 7736: 7733: 7731: 7728: 7726: 7723: 7721: 7718: 7716: 7713: 7711: 7708: 7706: 7703: 7701: 7698: 7696: 7693: 7691: 7688: 7686: 7683: 7682: 7680: 7678:Miscellaneous 7676: 7670: 7667: 7665: 7662: 7660: 7657: 7655: 7652: 7650: 7647: 7645: 7642: 7641: 7639: 7635: 7629: 7626: 7624: 7621: 7619: 7616: 7614: 7613:Samuel Bowles 7611: 7609: 7608:Roger Myerson 7606: 7604: 7601: 7599: 7598:Robert Aumann 7596: 7594: 7591: 7589: 7586: 7584: 7581: 7579: 7576: 7574: 7571: 7569: 7566: 7564: 7561: 7559: 7556: 7554: 7553:Lloyd Shapley 7551: 7549: 7546: 7544: 7541: 7539: 7538:Kenneth Arrow 7536: 7534: 7531: 7529: 7526: 7524: 7521: 7519: 7518:John Harsanyi 7516: 7514: 7511: 7509: 7506: 7504: 7501: 7499: 7496: 7494: 7491: 7489: 7488:Herbert Simon 7486: 7484: 7481: 7479: 7476: 7474: 7471: 7469: 7466: 7464: 7461: 7459: 7456: 7454: 7451: 7449: 7446: 7444: 7441: 7439: 7436: 7434: 7431: 7429: 7426: 7425: 7423: 7417: 7411: 7408: 7406: 7403: 7401: 7398: 7396: 7393: 7391: 7388: 7386: 7383: 7381: 7378: 7376: 7373: 7371: 7368: 7367: 7365: 7361: 7355: 7352: 7350: 7347: 7345: 7342: 7340: 7337: 7335: 7332: 7330: 7327: 7325: 7322: 7320: 7317: 7315: 7312: 7310: 7307: 7305: 7302: 7300: 7297: 7295: 7292: 7290: 7289:Fair division 7287: 7285: 7282: 7280: 7277: 7275: 7272: 7270: 7267: 7265: 7264:Dictator game 7262: 7260: 7257: 7255: 7252: 7250: 7247: 7245: 7242: 7240: 7237: 7235: 7232: 7230: 7227: 7225: 7222: 7220: 7217: 7215: 7212: 7210: 7207: 7205: 7202: 7200: 7197: 7195: 7192: 7190: 7187: 7185: 7182: 7180: 7177: 7175: 7172: 7170: 7167: 7165: 7162: 7160: 7157: 7155: 7152: 7151: 7149: 7147: 7143: 7137: 7136:Zero-sum game 7134: 7132: 7129: 7127: 7124: 7122: 7119: 7117: 7114: 7112: 7109: 7107: 7106:Repeated game 7104: 7102: 7099: 7097: 7094: 7092: 7089: 7087: 7085: 7081: 7079: 7076: 7074: 7071: 7069: 7066: 7064: 7061: 7059: 7056: 7055: 7053: 7051: 7045: 7039: 7036: 7034: 7031: 7029: 7026: 7024: 7023:Pure strategy 7021: 7019: 7016: 7014: 7011: 7009: 7006: 7004: 7001: 6999: 6996: 6994: 6991: 6989: 6988:De-escalation 6986: 6984: 6981: 6979: 6976: 6974: 6971: 6969: 6966: 6964: 6961: 6960: 6958: 6956: 6952: 6946: 6943: 6941: 6938: 6936: 6933: 6931: 6930:Shapley value 6928: 6926: 6923: 6921: 6918: 6916: 6913: 6911: 6908: 6906: 6903: 6901: 6898: 6896: 6893: 6891: 6888: 6886: 6883: 6881: 6878: 6876: 6873: 6871: 6868: 6866: 6863: 6861: 6858: 6856: 6853: 6851: 6848: 6846: 6843: 6841: 6838: 6836: 6833: 6831: 6828: 6826: 6823: 6822: 6820: 6818: 6814: 6810: 6804: 6801: 6799: 6798:Succinct game 6796: 6794: 6791: 6789: 6786: 6784: 6781: 6779: 6776: 6774: 6771: 6769: 6766: 6764: 6761: 6759: 6756: 6754: 6751: 6749: 6746: 6744: 6741: 6739: 6736: 6734: 6731: 6729: 6726: 6724: 6721: 6719: 6716: 6715: 6713: 6709: 6705: 6697: 6692: 6690: 6685: 6683: 6678: 6677: 6674: 6666: 6665:10.1.1.89.805 6661: 6654: 6653: 6647: 6645: 6641: 6638: 6636: 6633: 6631: 6627: 6626:Grundy's game 6624: 6623: 6619: 6610: 6606: 6602: 6598: 6593: 6588: 6584: 6580: 6573: 6570: 6565: 6561: 6554: 6551: 6547: 6541: 6537: 6533: 6532: 6527: 6523: 6522:Grundy, P. M. 6517: 6514: 6509: 6505: 6501: 6497: 6493: 6490:(in German). 6489: 6488: 6483: 6479: 6473: 6470: 6463: 6459: 6456: 6454: 6451: 6450: 6446: 6444: 6442: 6441: 6436: 6435: 6430: 6426: 6422: 6419:, notably by 6418: 6402: 6382: 6379: 6376: 6373: 6353: 6350: 6347: 6327: 6307: 6295: 6291: 6264: 6249: 6229: 6226: 6206: 6198: 6197: 6196: 6181: 6178: 6175: 6172: 6152: 6132: 6120: 6118: 6104: 6101: 6098: 6095: 6075: 6072: 6069: 6065: 6062: 6040: 6037: 6033: 6030: 6021: 6005: 6001: 5980: 5960: 5957: 5952: 5948: 5927: 5924: 5902: 5898: 5894: 5874: 5871: 5866: 5862: 5839: 5835: 5831: 5811: 5808: 5788: 5785: 5780: 5776: 5753: 5749: 5745: 5724: 5721: 5711: 5672: 5669: 5665: 5644: 5641: 5632: 5616: 5596: 5593: 5589: 5586: 5564: 5561: 5557: 5537: 5534: 5525: 5487: 5484: 5481: 5477: 5474: 5453: 5450: 5429: 5426: 5418:Suppose that 5416: 5402: 5399: 5396: 5392: 5389: 5344: 5341: 5338: 5334: 5331: 5321: 5306: 5303: 5299: 5296: 5251: 5248: 5244: 5241: 5196: 5193: 5171: 5168: 5145: 5141: 5137: 5117: 5095: 5091: 5069: 5066: 5062: 5059: 5039: 5018: 5015: 5011: 5008: 4999: 4983: 4979: 4956: 4952: 4948: 4945: 4942: 4937: 4933: 4929: 4924: 4920: 4911: 4895: 4875: 4872: 4869: 4866: 4841: 4837: 4833: 4830: 4827: 4824: 4819: 4815: 4811: 4808: 4803: 4799: 4795: 4789: 4785: 4782: 4759: 4755: 4751: 4748: 4743: 4739: 4730: 4709: 4705: 4701: 4698: 4695: 4690: 4686: 4682: 4677: 4673: 4666: 4663: 4654: 4652: 4644: 4642: 4627: 4624: 4620: 4617: 4597: 4589: 4585: 4569: 4561: 4560:associativity 4542: 4539: 4536: 4530: 4526: 4523: 4519: 4515: 4512: 4491: 4488: 4484: 4481: 4477: 4473: 4470: 4425: 4422: 4419: 4416: 4413: 4389: 4386: 4382: 4379: 4373: 4370: 4367: 4364: 4344: 4341: 4338: 4335: 4332: 4287: 4284: 4280: 4277: 4274: 4271: 4262: 4248: 4204: 4201: 4198: 4178: 4175: 4172: 4164: 4163:commutativity 4147: 4144: 4140: 4137: 4117: 4114: 4110: 4107: 4086: 4083: 4080: 4059: 4056: 4052: 4049: 4040: 4001: 3998: 3994: 3991: 3970: 3967: 3963: 3960: 3948: 3946: 3943: 3929: 3926: 3923: 3879: 3876: 3873: 3870: 3867: 3823: 3803: 3800: 3797: 3729: 3726: 3723: 3720: 3717: 3673: 3670: 3667: 3658: 3620: 3617: 3614: 3611: 3608: 3588: 3585: 3582: 3562: 3559: 3556: 3512: 3492: 3472: 3452: 3449: 3446: 3443: 3440: 3396: 3393: 3390: 3383:Suppose that 3381: 3367: 3347: 3344: 3341: 3338: 3335: 3315: 3312: 3309: 3289: 3286: 3283: 3280: 3277: 3257: 3213: 3201: 3199: 3181: 3178: 3173: 3169: 3120: 3117: 3112: 3108: 3075: 3033: 3030: 3007: 2974: 2970: 2965: 2951: 2948: 2944: 2941: 2920: 2917: 2914: 2894: 2870: 2867: 2863: 2860: 2840: 2832: 2831: 2813: 2810: 2789: 2780: 2742: 2739: 2695: 2692: 2684: 2683: 2655: 2654: 2626: 2625: 2616: 2614: 2597: 2594: 2591: 2588: 2584: 2581: 2577: 2574: 2568: 2561: 2558: 2554: 2550: 2547: 2543: 2539: 2536: 2532: 2529: 2523: 2519: 2516: 2512: 2509: 2500: 2453: 2450: 2447: 2441: 2438: 2432: 2429: 2426: 2420: 2411: 2408: 2399: 2393: 2390: 2380: 2375: 2372: 2367: 2357: 2354: 2351: 2345: 2342: 2336: 2333: 2330: 2324: 2321: 2318: 2311: 2306: 2303: 2298: 2291: 2288: 2285: 2279: 2276: 2270: 2267: 2264: 2257: 2252: 2249: 2237: 2223: 2220: 2213: 2209: 2198: 2193: 2190: 2185: 2181: 2172: 2171:combined game 2167: 2153: 2140: 2137: 2124: 2120: 2117: 2093: 2090: 2080: 2075: 2044: 2041: 2038: 2032: 2029: 2023: 2020: 2017: 2011: 2002: 1999: 1990: 1984: 1981: 1968: 1955: 1952: 1949: 1943: 1940: 1934: 1931: 1928: 1922: 1919: 1916: 1906: 1896: 1893: 1890: 1884: 1881: 1875: 1872: 1869: 1852: 1849: 1827: 1818: 1807:Combined Game 1806: 1804: 1789: 1786: 1764: 1761: 1739: 1736: 1715: 1695: 1675: 1667: 1666:first example 1655: 1653: 1638: 1635: 1613: 1610: 1588: 1585: 1576: 1575: 1566: 1564: 1562: 1558: 1554: 1549: 1532: 1529: 1523: 1520: 1517: 1514: 1508: 1505: 1502: 1496: 1476: 1473: 1470: 1463:and for all 1447: 1444: 1441: 1438: 1435: 1429: 1426: 1423: 1400: 1397: 1391: 1388: 1385: 1342: 1339: 1319: 1299: 1296: 1288: 1287: 1286: 1268: 1265: 1245: 1242: 1222: 1219: 1207: 1191: 1171: 1168: 1165: 1159: 1156: 1150: 1147: 1144: 1138: 1129: 1126: 1117: 1111: 1108: 1095: 1082: 1079: 1076: 1070: 1067: 1061: 1058: 1055: 1049: 1046: 1043: 1033: 1023: 1020: 1017: 1011: 1008: 1002: 999: 996: 974: 960: 950: 947: 944: 938: 935: 932: 926: 923: 917: 914: 911: 893: 871: 868: 865: 859: 856: 850: 847: 844: 817: 814: 791: 788: 785: 782: 779: 768: 752: 749: 729: 726: 718: 699: 696: 673: 670: 662: 644: 641: 618: 615: 606: 591: 588: 565: 562: 551: 535: 532: 524: 520: 505: 502: 471: 470: 462: 460: 457: 432: 427: 424: 420: 419: 413: 409: 408: 407: 400: 377: 365: 359: 356: 353: 330: 310: 302: 298: 297: 292: 291: 285: 283: 279: 275: 271: 267: 266: 257: 255: 253: 249: 248:R. P. Sprague 244: 243:of the game. 242: 237: 233: 228: 226: 222: 218: 214: 210: 206: 202: 198: 187: 184: 169: 166: 158: 148: 144: 138: 135:This article 133: 124: 123: 114: 111: 103: 93: 89: 83: 82: 76: 71: 62: 61: 56: 54: 47: 46: 41: 40: 35: 30: 21: 20: 7583:Peyton Young 7578:Paul Milgrom 7493:Hervé Moulin 7433:Amos Tversky 7404: 7375:Folk theorem 7086:-player game 7083: 7008:Grim trigger 6651: 6644:sputsoft.com 6630:cut-the-knot 6582: 6578: 6572: 6563: 6559: 6553: 6545: 6540:the original 6535: 6529: 6516: 6491: 6485: 6472: 6453:Genus theory 6438: 6432: 6299: 6124: 6022: 5712: 5630: 5526: 5417: 5322: 5000: 4655: 4648: 4588:transitivity 4263: 4041: 3952: 3949:Second Lemma 3944: 3659: 3382: 3205: 3073: 2966: 2829: 2828: 2781: 2681: 2680: 2652: 2651: 2623: 2622: 2620: 2501: 2168: 2076: 1814: 1663: 1573: 1572: 1570: 1560: 1556: 1552: 1550: 1283: 1282: 1211: 766: 716: 549: 522: 458: 430: 428: 417: 416: 404: 403: 401: 300: 295: 294: 289: 288: 286: 281: 277: 264: 263: 261: 252:P. M. Grundy 245: 241:nim-sequence 240: 235: 232:Grundy value 231: 229: 200: 194: 179: 161: 152: 136: 106: 97: 78: 50: 43: 37: 36:Please help 33: 7700:Coopetition 7503:Jean Tirole 7498:John Conway 7478:Eric Maskin 7274:Blotto game 7259:Pirate game 7068:Global game 7038:Tit for tat 6973:Bid shading 6963:Appeasement 6813:Equilibrium 6793:Solved game 6728:Determinacy 6711:Definitions 6704:game theory 6566:(2): 221–22 6494:: 438–444. 6421:Richard Guy 6121:Development 5710:-position. 5524:-position. 4039:-position. 3742:is also an 3657:-position. 3202:First Lemma 2779:-position. 2617:Equivalence 552:is written 258:Definitions 250:(1936) and 92:introducing 7750:Categories 7344:Trust game 7329:Kuhn poker 6998:Escalation 6993:Deterrence 6983:Cheap talk 6955:Strategies 6773:Preference 6702:Topics of 6508:0013.29004 6500:62.1070.03 6464:References 6165:such that 5609:. Because 4438:is also a 4217:must be a 3892:must be a 3250:-position 3226:and every 2830:equivalent 2682:- position 2653:- position 207:under the 75:references 39:improve it 7528:John Nash 7234:Stag hunt 6978:Collusion 6660:CiteSeerX 6374:∗ 6227:∗ 6179:∗ 6176:≈ 6102:∗ 6099:≈ 6073:∗ 6070:≈ 6034:≈ 5925:∗ 5895:∗ 5832:∗ 5809:∗ 5746:∗ 5666:∗ 5558:∗ 5535:∗ 5485:∗ 5451:∗ 5400:∗ 5397:≈ 5342:∗ 5300:≈ 5138:∗ 5012:≈ 4946:… 4873:∗ 4870:≈ 4834:∗ 4828:… 4812:∗ 4796:∗ 4774:. So let 4752:∗ 4749:≈ 4727:. By the 4699:… 4621:≈ 4598:≈ 4570:≈ 4520:≈ 4478:≈ 4368:≈ 4336:≈ 4053:≈ 3964:≈ 3281:≈ 3174:≈ 2892:∀ 2864:≈ 2740:∗ 2693:∗ 2595:∈ 2589:∣ 2569:∪ 2555:∈ 2544:∣ 2451:∗ 2439:∗ 2427:∗ 2409:∗ 2391:∗ 2355:∗ 2343:∗ 2331:∗ 2319:∗ 2289:∗ 2277:∗ 2265:∗ 2238:∪ 2221:∗ 2138:∗ 2042:∗ 2030:∗ 2018:∗ 2000:∗ 1982:∗ 1953:∗ 1941:∗ 1929:∗ 1917:∗ 1894:∗ 1882:∗ 1870:∗ 1530:∗ 1524:∪ 1518:∗ 1497:∗ 1474:≥ 1445:∗ 1436:∗ 1424:∗ 1398:∗ 1386:∗ 1340:∗ 1297:∗ 1266:∗ 1243:∗ 1220:∗ 1169:∗ 1157:∗ 1145:∗ 1127:∗ 1109:∗ 1080:∗ 1068:∗ 1056:∗ 1044:∗ 1021:∗ 1009:∗ 997:∗ 948:∗ 936:∗ 924:∗ 912:∗ 869:∗ 857:∗ 845:∗ 815:∗ 789:∗ 780:∗ 750:∗ 727:∗ 697:∗ 671:∗ 642:∗ 616:∗ 589:∗ 563:∗ 533:∗ 503:∗ 431:zero game 418:impartial 301:zero game 236:nim-value 155:June 2014 100:June 2014 45:talk page 7669:Lazy SMP 7363:Theorems 7314:Deadlock 7169:Checkers 7050:of games 6817:concepts 6524:(1939). 6480:(1936). 6447:See also 6066:′ 6041:′ 5973:because 5725:′ 5673:′ 5645:′ 5629:was the 5590:′ 5565:′ 5478:′ 5430:′ 5393:′ 5335:′ 5307:′ 5252:′ 5197:′ 5172:′ 5070:′ 5019:′ 4888:, where 4786:′ 4628:′ 4527:′ 4516:′ 4485:′ 4474:′ 4390:′ 4288:′ 4148:′ 4111:′ 4060:′ 4002:′ 3971:′ 3525:being a 3182:′ 3121:′ 3034:′ 2945:′ 2871:′ 2814:′ 2585:′ 2562:′ 2551:′ 2540:′ 2520:′ 2376:′ 2307:′ 2253:′ 2194:′ 2121:′ 2094:′ 2077:For the 1790:′ 1765:′ 1740:′ 1639:′ 1614:′ 1589:′ 1563:nimber. 550:position 423:checkers 290:position 254:(1939). 7421:figures 7204:Chicken 7058:Auction 7048:Classes 6609:7175146 6548:: 9–11. 6340:, then 6294:nim-sum 5631:minimum 4908:is the 4357:, that 4191:. But 1285:nimbers 1208:Nimbers 141:Please 88:improve 6662:  6607:  6531:Eureka 6506:  6498:  5578:where 4582:is an 4558:. By 3686:is an 2973:second 2755:is an 1778:, and 1627:, and 1574:adding 1561:single 1258:, and 548:, her 225:nimber 199:, the 77:, but 7159:Chess 7146:Games 6656:(PDF) 6605:S2CID 6587:arXiv 6242:) is 5768:. If 5357:is a 5265:is a 4645:Proof 4504:that 4301:is a 4015:is a 3409:is a 3137:is a 3021:and 2969:first 2708:is a 1661:wins. 765:, so 742:and 296:moves 6840:Core 6437:and 6054:and 5872:> 5786:< 5594:< 5443:and 3328:and 3048:are 2971:and 2827:are 2802:and 523:move 468:wins 265:game 230:The 7419:Key 6642:at 6628:at 6597:doi 6564:123 6504:Zbl 6496:JFM 6125:If 6020:.) 5917:to 5824:to 5658:to 5160:in 5110:in 4590:of 4161:by 3198:.) 3074:Bob 1557:nim 1553:nim 1355:is 767:her 717:His 412:nim 402:An 272:of 234:or 213:nim 195:In 145:to 7752:: 7154:Go 6658:, 6603:. 6595:. 6581:. 6562:, 6546:27 6534:. 6528:. 6502:. 6492:41 6484:. 6443:. 6427:, 6423:, 5320:. 4998:. 4641:. 3942:. 3380:. 2964:. 2907:, 1803:: 1753:, 1728:, 1708:, 1688:, 1652:. 1602:, 1548:. 1489:, 1416:, 1378:, 1235:, 48:. 7084:n 6695:e 6688:t 6681:v 6611:. 6599:: 6589:: 6583:6 6536:2 6510:. 6403:H 6383:H 6380:+ 6377:m 6354:H 6351:+ 6348:G 6328:m 6308:G 6275:P 6262:; 6250:m 6230:m 6207:m 6182:m 6173:G 6153:m 6133:G 6105:m 6096:G 6076:m 6063:G 6038:G 6031:G 6006:i 6002:n 5981:m 5961:m 5958:= 5953:i 5949:n 5928:m 5903:i 5899:n 5875:m 5867:i 5863:n 5840:i 5836:n 5812:m 5789:m 5781:i 5777:n 5754:i 5750:n 5722:G 5696:P 5670:m 5642:G 5617:m 5597:m 5587:m 5562:m 5538:m 5510:P 5488:m 5482:+ 5475:G 5454:m 5427:G 5403:m 5390:G 5367:P 5345:m 5339:+ 5332:G 5304:G 5297:G 5275:P 5249:G 5245:+ 5242:G 5220:P 5194:G 5169:G 5146:i 5142:n 5118:G 5096:i 5092:G 5067:G 5063:+ 5060:G 5040:k 5016:G 5009:G 4984:i 4980:n 4957:k 4953:n 4949:, 4943:, 4938:2 4934:n 4930:, 4925:1 4921:n 4896:m 4876:m 4867:G 4847:} 4842:k 4838:n 4831:, 4825:, 4820:2 4816:n 4809:, 4804:1 4800:n 4793:{ 4790:= 4783:G 4760:i 4756:n 4744:i 4740:G 4715:} 4710:k 4706:G 4702:, 4696:, 4691:2 4687:G 4683:, 4678:1 4674:G 4670:{ 4667:= 4664:G 4625:G 4618:G 4546:) 4543:G 4540:+ 4537:G 4534:( 4531:+ 4524:G 4513:G 4492:B 4489:+ 4482:G 4471:G 4448:P 4426:G 4423:+ 4420:G 4417:= 4414:B 4394:) 4387:G 4383:+ 4380:G 4377:( 4374:+ 4371:G 4365:G 4345:A 4342:+ 4339:G 4333:G 4311:P 4285:G 4281:+ 4278:G 4275:= 4272:A 4249:G 4227:P 4205:G 4202:+ 4199:G 4179:G 4176:+ 4173:G 4145:G 4141:+ 4138:G 4118:G 4115:+ 4108:G 4087:G 4084:= 4081:H 4057:G 4050:G 4025:P 3999:G 3995:+ 3992:G 3968:G 3961:G 3930:H 3927:+ 3924:G 3902:N 3880:H 3877:+ 3874:G 3871:+ 3868:A 3846:P 3824:A 3804:H 3801:+ 3798:G 3776:P 3752:N 3730:H 3727:+ 3724:G 3721:+ 3718:A 3696:N 3674:H 3671:+ 3668:G 3643:P 3621:H 3618:+ 3615:G 3612:+ 3609:A 3589:H 3586:+ 3583:G 3563:H 3560:+ 3557:G 3535:P 3513:A 3493:A 3473:A 3453:H 3450:+ 3447:G 3444:+ 3441:A 3419:P 3397:H 3394:+ 3391:G 3368:H 3348:H 3345:+ 3342:G 3339:+ 3336:A 3316:H 3313:+ 3310:G 3290:G 3287:+ 3284:A 3278:G 3258:A 3236:P 3214:G 3179:S 3170:S 3147:P 3118:S 3113:+ 3109:S 3086:N 3058:N 3031:S 3008:S 2985:P 2952:H 2949:+ 2942:G 2921:H 2918:+ 2915:G 2895:H 2868:G 2861:G 2841:H 2811:G 2790:G 2765:N 2743:1 2718:P 2696:0 2666:P 2637:N 2601:} 2598:S 2592:s 2582:S 2578:+ 2575:s 2572:{ 2566:} 2559:S 2548:s 2537:s 2533:+ 2530:S 2527:{ 2524:= 2517:S 2513:+ 2510:S 2466:} 2460:} 2457:} 2454:2 2448:, 2445:} 2442:1 2436:{ 2433:, 2430:1 2424:{ 2421:, 2418:} 2415:} 2412:1 2406:{ 2403:{ 2400:, 2397:} 2394:1 2388:{ 2385:{ 2381:+ 2373:S 2368:, 2364:} 2361:} 2358:2 2352:, 2349:} 2346:1 2340:{ 2337:, 2334:1 2328:{ 2325:, 2322:2 2316:{ 2312:+ 2304:S 2299:, 2295:} 2292:2 2286:, 2283:} 2280:1 2274:{ 2271:, 2268:1 2262:{ 2258:+ 2250:S 2243:{ 2233:} 2227:} 2224:1 2218:{ 2214:+ 2210:S 2204:{ 2199:= 2191:S 2186:+ 2182:S 2154:. 2149:} 2144:} 2141:1 2135:{ 2130:{ 2125:= 2118:S 2091:S 2060:} 2053:} 2048:} 2045:2 2039:, 2036:} 2033:1 2027:{ 2024:, 2021:1 2015:{ 2012:, 2009:} 2006:} 2003:1 1997:{ 1994:{ 1991:, 1988:} 1985:1 1979:{ 1974:{ 1969:, 1964:} 1959:} 1956:2 1950:, 1947:} 1944:1 1938:{ 1935:, 1932:1 1926:{ 1923:, 1920:2 1912:{ 1907:, 1902:} 1897:2 1891:, 1888:} 1885:1 1879:{ 1876:, 1873:1 1865:{ 1858:{ 1853:= 1850:S 1828:S 1787:C 1762:B 1737:A 1716:C 1696:B 1676:A 1636:C 1611:B 1586:A 1536:} 1533:n 1527:{ 1521:n 1515:= 1512:) 1509:1 1506:+ 1503:n 1500:( 1477:0 1471:n 1451:} 1448:1 1442:, 1439:0 1433:{ 1430:= 1427:2 1404:} 1401:0 1395:{ 1392:= 1389:1 1366:} 1363:{ 1343:0 1320:n 1300:n 1269:2 1246:1 1223:0 1192:. 1187:} 1180:} 1175:} 1172:2 1166:, 1163:} 1160:1 1154:{ 1151:, 1148:1 1142:{ 1139:, 1136:} 1133:} 1130:1 1124:{ 1121:{ 1118:, 1115:} 1112:1 1106:{ 1101:{ 1096:, 1091:} 1086:} 1083:2 1077:, 1074:} 1071:1 1065:{ 1062:, 1059:1 1053:{ 1050:, 1047:2 1039:{ 1034:, 1029:} 1024:2 1018:, 1015:} 1012:1 1006:{ 1003:, 1000:1 992:{ 985:{ 961:. 956:} 951:2 945:, 942:} 939:2 933:, 930:} 927:1 921:{ 918:, 915:1 909:{ 904:{ 891:. 877:} 872:2 866:, 863:} 860:1 854:{ 851:, 848:1 840:{ 818:2 795:} 792:1 786:, 783:0 777:{ 753:1 730:0 703:} 700:1 694:{ 674:1 660:. 648:} 645:1 639:{ 619:1 604:. 592:1 569:} 566:0 560:{ 536:0 518:. 506:0 483:} 480:{ 444:} 441:{ 387:) 384:} 381:{ 378:, 375:} 372:{ 369:( 366:= 363:) 360:B 357:, 354:A 351:( 331:B 311:A 186:) 180:( 168:) 162:( 157:) 153:( 139:. 113:) 107:( 102:) 98:( 84:. 55:) 51:(

Index

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combinatorial game theory
impartial game
normal play convention
nim
natural number
ordinal number
nimber
R. P. Sprague
P. M. Grundy
sequential game
perfect information
impartial game
nim
checkers
nimbers
first example
first example game
second example game

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