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Cram (game)

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as the unique number n such that G+n is a second player win in misère play. Even if it looks very similar to the usual Grundy-value in normal play, it is not as powerful. In particular, it is not possible to deduce the misère Grundy value of a sum of games only from their respective misère Grundy
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In 2009, Martin Schneider computed the misère grundy values up to the 3 Ă— 9, 4 Ă— 6, and 5 Ă— 5 board. In 2010, Julien Lemoine and Simon Viennot extended these results up to the 3 Ă— 15, 4 Ă— 9 and 5 Ă— 7 boards, along with the value of the
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play. This means that for any move by Player 1, Player 2 has a corresponding symmetric move across the horizontal and vertical axes. In a sense, player 2 'mimics' the moves made by Player 1. If Player 2 follows this strategy, Player 2 will always make the last move, and thus win the game.
345:. It allowed them to compute the Grundy values up to the 3 Ă— 20, 4 Ă— 9, 5 Ă— 9, 6 Ă— 7 and 7 Ă— 7 boards. Piotr Beling extended these results up to the 6 Ă— 9, 7 Ă— 8, and 7 Ă— 9 boards. 141:
In the even-by-odd case, the first player wins by similar symmetry play. Player 1 places their first domino in the center two squares on the grid. Player 2 then makes their move, but Player 1 can play symmetrically thereafter, thus ensuring a win for Player 1.
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In 2009, Martin Schneider computed the Grundy values up to the 3 Ă— 9, 4 Ă— 5 and 5 Ă— 7 boards. In 2010, Julien Lemoine and Simon Viennot applied to the game of Cram algorithms that were initially developed for the game of
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which they place on the grid in turn. A player can place a domino either horizontally or vertically. Contrary to the related game of Domineering, the possible moves are the same for the two players, and Cram is then an
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and the only difference in the rules is that players may place their dominoes in either orientation, but it results in a very different game. It has been called by many names, including "plugg" by
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The symmetry strategy implies that even-by-even boards have a Grundy value of 0, but in the case of even-by-odd boards it only implies a Grundy value greater or equal to 1.
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As for all impartial games, there are two possible conventions for victory: in the normal game, the first player who cannot move loses, and on the contrary, in the
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The game is played on a sheet of graph paper, with any set of designs traced out. It is most commonly played on rectangular board like a 6Ă—6 square or a
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boards, from n=1 to n=15 is: 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1. This sequence is conjectured to be periodic of period 3.
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boards, from n=1 to n=20 is: 1, 1, 0, 1, 1, 4, 1, 3, 1, 2, 0, 1, 2, 3, 1, 4, 0, 1, 0, 2. It doesn't appear to show any pattern.
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for normal Cram is simple for even-by-even boards and even-by-odd boards. In the even-by-even case, the second player wins by
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The table below details the known results for boards with both dimensions greater than 3. Since the value of an
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The adjacent table details the known misère results for boards with both dimensions greater than 3.
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indicates that in the normal version any Cram position is equivalent to a
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version, because in that case it would only ensure the player that they
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The sequence of currently known misère Grundy values for 3 Ă— 
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Example of a Cram game. In the normal version, the blue player wins.
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Julien, Lemoine; Simon, Viennot (2010). "Nimbers are inevitable".
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The sequence of currently known Grundy values for 3 Ă— 
175: 98:, but it can also be played on an entirely irregular 384:The misère Grundy-value of a game G is defined by 371:board, we give only the upper part of the table. 76:, and "dots-and-pairs". Cram was popularized by 121:version, the first player who cannot move wins. 584:"Solving Cram Using Combinational Game Theory" 642:Computation records of normal and misère Cram 637: 635: 633: 8: 644:, Julien Lemoine and Simon Viennot web site 599: 597: 145:Symmetry play is a useless strategy in the 654:Rust software for solving impartial games 621: 536:Winning Ways for Your Mathematical Plays 184:Winning Ways for your Mathematical Plays 606:, Martin Schneider, Master thesis, 2009 544: 397:Misère Grundy values for large boards 7: 363:board is the same as the value of a 569:10.1038/scientificamerican0374-102 186:, in particular the 2 Ă—  25: 178:of a given size, also called the 105:Two players have a collection of 64:(or any type of grid). It is the 582:Uiterwijk, Jos (December 2020). 182:. Some values can be found in 1: 190:board, whose value is 0 if 723: 30:This article is about the 29: 702:Combinatorial game theory 38:version of the game, see 102:or a cylindrical board. 692:Abstract strategy games 502:6 Ă— 6 board. 707:Paper-and-pencil games 172:Sprague–Grundy theorem 50: 60:played on a sheet of 48: 672:On Numbers and Games 390:On Numbers and Games 557:Scientific American 523:Berlekamp, Elwyn R. 398: 380:Misère Grundy-value 209: 83:Scientific American 74:Geoffrey Mott-Smith 697:Mathematical games 675:. A K Peters, Ltd. 539:. A K Peters, Ltd. 396: 204: 51: 604:Das Spiel Juvavum 499: 498: 333: 332: 208:for large boards 194:is even and 1 if 166:Since Cram is an 58:mathematical game 34:of Cram. For the 27:Mathematical game 16:(Redirected from 714: 677: 676: 663: 657: 651: 645: 639: 628: 627: 625: 613: 607: 601: 592: 591: 579: 573: 572: 549: 540: 399: 210: 21: 722: 721: 717: 716: 715: 713: 712: 711: 682: 681: 680: 667:John H., Conway 665: 664: 660: 652: 648: 640: 631: 615: 614: 610: 602: 595: 581: 580: 576: 553:Gardner, Martin 551: 550: 546: 531:Guy, Richard K. 527:Conway, John H. 521: 518: 382: 377: 338: 164: 159: 127: 92: 43: 28: 23: 22: 15: 12: 11: 5: 720: 718: 710: 709: 704: 699: 694: 684: 683: 679: 678: 658: 646: 629: 608: 593: 574: 563:(2): 106–108. 543: 542: 541: 517: 514: 497: 496: 493: 490: 487: 484: 481: 478: 474: 473: 470: 467: 464: 461: 458: 455: 451: 450: 447: 444: 441: 438: 435: 432: 428: 427: 424: 421: 418: 415: 412: 409: 381: 378: 376: 375:Misère version 373: 337: 334: 331: 330: 327: 324: 321: 318: 315: 312: 308: 307: 304: 301: 298: 295: 292: 289: 285: 284: 281: 278: 275: 272: 269: 266: 262: 261: 258: 255: 252: 249: 246: 243: 239: 238: 235: 232: 229: 226: 223: 220: 168:impartial game 163: 160: 158: 157:Normal version 155: 126: 123: 112:impartial game 91: 88: 78:Martin Gardner 32:impartial game 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 719: 708: 705: 703: 700: 698: 695: 693: 690: 689: 687: 674: 673: 668: 662: 659: 655: 650: 647: 643: 638: 636: 634: 630: 624: 619: 612: 609: 605: 600: 598: 594: 589: 585: 578: 575: 570: 566: 562: 558: 554: 548: 545: 538: 537: 532: 528: 524: 520: 519: 515: 513: 510: 508: 503: 494: 491: 488: 485: 482: 479: 476: 475: 471: 468: 465: 462: 459: 456: 453: 452: 448: 445: 442: 439: 436: 433: 430: 429: 425: 422: 419: 416: 413: 410: 408: 405: Ă—  404: 401: 400: 394: 391: 387: 379: 374: 372: 370: 367: Ă—  366: 362: 359: Ă—  358: 353: 351: 346: 344: 335: 328: 325: 322: 319: 316: 313: 310: 309: 305: 302: 299: 296: 293: 290: 287: 286: 282: 279: 276: 273: 270: 267: 264: 263: 259: 256: 253: 250: 247: 244: 241: 240: 236: 233: 230: 227: 224: 221: 219: 216: Ă—  215: 212: 211: 207: 206:Grundy values 202: 199: 197: 193: 189: 185: 181: 177: 173: 169: 161: 156: 154: 152: 148: 143: 139: 136: 132: 125:Symmetry play 124: 122: 120: 115: 113: 108: 103: 101: 97: 89: 87: 85: 84: 79: 75: 71: 67: 63: 59: 55: 47: 41: 37: 33: 19: 670: 661: 656:Piotr Beling 649: 611: 588:ResearchGate 587: 577: 560: 556: 547: 534: 511: 506: 504: 500: 406: 402: 383: 368: 364: 360: 356: 354: 349: 347: 339: 336:Known values 217: 213: 200: 195: 191: 187: 180:Grundy value 179: 165: 162:Grundy value 150: 144: 140: 129:The winning 128: 116: 104: 96:checkerboard 93: 81: 53: 52: 18:Cram (games) 70:Domineering 68:version of 62:graph paper 40:Domineering 686:Categories 516:References 623:1011.5841 66:impartial 669:(2000). 533:(2003). 393:values. 198:is odd. 176:nim-heap 135:symmetry 131:strategy 107:dominoes 36:partisan 343:Sprouts 100:polygon 386:Conway 170:, the 147:misère 119:misère 618:arXiv 90:Rules 56:is a 151:lose 54:Cram 565:doi 561:230 388:in 80:in 688:: 632:^ 596:^ 586:. 559:. 529:; 525:; 495:? 477:6 472:? 454:5 449:1 431:4 426:9 329:1 311:7 306:1 288:6 283:1 265:5 260:1 242:4 237:9 153:. 114:. 86:. 626:. 620:: 590:. 571:. 567:: 507:n 492:? 489:? 486:1 483:- 480:- 469:? 466:1 463:1 460:2 457:- 446:1 443:1 440:0 437:0 434:0 423:8 420:7 417:6 414:5 411:4 407:m 403:n 369:n 365:m 361:m 357:n 350:n 326:3 323:1 320:- 317:- 314:- 303:0 300:5 297:0 294:- 291:- 280:1 277:1 274:2 271:0 268:- 257:0 254:3 251:0 248:2 245:0 234:8 231:7 228:6 225:5 222:4 218:m 214:n 196:n 192:n 188:n 42:. 20:)

Index

Cram (games)
impartial game
partisan
Domineering

mathematical game
graph paper
impartial
Domineering
Geoffrey Mott-Smith
Martin Gardner
Scientific American
checkerboard
polygon
dominoes
impartial game
misère
strategy
symmetry
misère
impartial game
Sprague–Grundy theorem
nim-heap
Winning Ways for your Mathematical Plays
Grundy values
Sprouts
Conway
On Numbers and Games
Berlekamp, Elwyn R.
Conway, John H.

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