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Parity game

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2882: 20: 1106: 661: 1101:{\displaystyle {\begin{aligned}Attr_{i}(U)^{0}&:=U\\Attr_{i}(U)^{j+1}&:=Attr_{i}(U)^{j}\cup \{v\in V_{i}\mid \exists (v,w)\in E:w\in Attr_{i}(U)^{j}\}\cup \{v\in V_{1-i}\mid \forall (v,w)\in E:w\in Attr_{i}(U)^{j}\}\\Attr_{i}(U)&:=\bigcup _{j=0}^{\infty }Attr_{i}(U)^{j}\end{aligned}}} 46:
The winner of a finite play is the player whose opponent is unable to move. The winner of an infinite play is determined by the priorities appearing in the play. Typically, player 0 wins an infinite play if the largest priority that occurs infinitely often in the play is even. Player 1 wins
39:. Two players, 0 and 1, move a (single, shared) token along the edges of the graph. The owner of the node that the token falls on selects the successor node (does the next move). The players keep moving the token, resulting in a (possibly infinite) 2846:
Parity is the special case where every vertex has a single color. Specifically, in the above bipartite graph scenario, the problem now is to determine if there is a choice function selecting a single out-going edge from each vertex of
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Moreover, parity games are history-free determined. This means that if a player has a winning strategy then that player has a winning strategy that depends only on the current board position, and not on the history of the play.
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Zielonka's algorithm is based on a recursive descent on the number of priorities. If the maximal priority is 0, it is immediate to see that player 0 wins the whole game (with an arbitrary strategy). Otherwise, let
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Given that parity games are history-free determined, solving a given parity game is equivalent to solving the following simple looking graph-theoretic problem. Given a finite colored directed
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A parity game. Circular nodes belong to player 0, rectangular nodes belong to player 1. On the left side is the winning region of player 0, on the right side is the winning region of player 1.
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Despite its interesting complexity theoretic status, parity game solving can be seen as the algorithmic backend to problems in automated verification and controller synthesis. The
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a parity game played on a finite graph means deciding, for a given starting position, which of the two players has a winning strategy. It has been shown that this problem is in
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and C. S. Jutla: Tree Automata, Mu-Calculus and Determinacy, IEEE Proc. Foundations of Computer Science, pp 368–377 (1991),
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for instance is known to be equivalent to parity game solving. Also, decision problems like validity or satisfiability for
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Note that as opposed to parity games, this game is no longer symmetric with respect to players 0 and 1.
2560: 2068: 1859: 240:, such that the resulting subgraph has the property that in each cycle the largest occurring color is even. 3191: 2855: 2500: 421: 2807:
A slight modification of the above game, and the related graph-theoretic problem, makes solving the game
2219: 1973: 1118: 375: 158: 90: 70: 1936: 2287: 1517: 1451: 1228: 1176: 2322: 1288: 2453: 2025: 1381: 490: 613: 556: 2141: 1811: 1771: 1709: 1569: 1605: 3001:"Infinite Games on Finitely Coloured Graphs with Applications to Automata on Infinite Trees" 1668: 1225:) with a single edge and all nodes belonging to player 1 that must reach the previous set ( 516: 348: 321: 216: 137: 66: 3033: 2989:
A. Mostowski: Games with forbidden positions, University of Gdansk, Tech. Report 78 (1991)
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Infinite games on finitely coloured graphs with applications to automata on infinite tree
2191: 1745: 1642: 40: 2894: 1492: 35:, where each node has been colored by a priority – one of (usually) finitely many 3115: 2950: 2854:, such that the resulting subgraph has the property that in each cycle (and hence each 3064: 3052: 3017: 3000: 2919:: Borel determinacy, The Annals of Mathematics, Vol 102 No. 2 pp. 363–371 (1975) 3140: 3101: 2974: 78: 3048: 3012: 2942: 2916: 213:, is there a choice function selecting a single out-going edge from each vertex of 62: 3065:
Calude, Cristian S; Jain, Sanjay; Khoussainov, Bakhadyr; Li, Wei; Stephan, Frank,
2930: 2812: 148: 133: 125: 51: 36: 3093: 2890: 2881: 141: 32: 3166: 3180: 3085: 2970: 19: 1173:) one adds all nodes belonging to player 0 that can reach the previous set ( 140:). It remains an open question whether this decision problem is solvable in 104: 3089: 2898: 86: 55: 2954: 2130: 2931:"Decidability of second-order theories and automata on infinite trees" 248:
Zielonka outlined a recursive algorithm that solves parity games. Let
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Two state-of-the-art parity game solving toolsets are the following:
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leads to a relatively simple proof of determinacy of parity games.
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Zielonka's algorithm is based on the notation of attractors. Let
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such that infinitely many vertices in the play have color
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otherwise. This explains the word "parity" in the title.
2793:{\displaystyle W_{i},W_{1-i}:=W_{i}'',W_{1-i}''\cup B} 61:
Games related to parity games were implicitly used in
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are the sets of nodes belonging to player 0 resp. 1,
351: 324: 254: 219: 161: 2701:{\displaystyle W_{0}'',W_{1}'':=solve(G\setminus B)} 106: 2792: 2700: 2622: 2550: 2487: 2441:{\displaystyle W_{0}',W_{1}':=solve(G\setminus A)} 2440: 2362: 2312: 2263: 2206: 2171: 2118: 2057: 2014: 1962: 1921: 1836: 1796: 1760: 1734: 1687: 1657: 1627: 1594: 1558: 1506: 1477: 1421: 1366: 1313: 1269: 1217: 1165: 1100: 647: 590: 537: 505: 476: 442: 410: 364: 337: 310: 232: 193: 3031: 2935:Transactions of the American Mathematical Society 477:{\displaystyle \Omega :V\rightarrow \mathbb {N} } 3178: 2885:Most common applications of parity game solving. 1856:-attractor). We therefore compute the attractor 1742:is not empty, we only know for sure that player 1321:be the player associated with the priority. Let 1111:In other words, one starts with the initial set 655:. It can be defined by a fix-point computation: 3067:"Deciding parity games in quasipolynomial time" 1514:by recursion and obtain a pair of winning sets 1489:are removed. We can now solve the smaller game 112:Can parity games be solved in polynomial time? 3135:E. Grädel, W. Thomas, T. Wilke (Eds.) : 3120:: CS1 maint: multiple names: authors list ( 2545: 2542: 2482: 2479: 2258: 2255: 2133:, the algorithm might be expressed as this: 1361: 1334: 996: 900: 894: 804: 244:Recursive algorithm for solving parity games 116:(more unsolved problems in computer science) 16:Mathematical game played on a directed graph 1437:can now ensure that every play that visits 311:{\displaystyle G=(V,V_{0},V_{1},E,\Omega )} 50:Parity games lie in the third level of the 3016: 2803:Related games and their decision problems 1485:in which all nodes and affected edges of 1429:be the corresponding attractor of player 470: 3098:Finite model theory and its applications 2998: 2880: 1367:{\displaystyle U=\{v\mid \Omega (v)=p\}} 18: 2941:. American Mathematical Society: 1–35. 2901:can be reduced to parity game solving. 2877:Relation with logic and automata theory 2623:{\displaystyle B:=Attr_{1-i}(W_{1-i}')} 2119:{\displaystyle W_{1-i}=W''_{1-i}\cup B} 1699:which also results in a win for player 1277:) no matter which edge player 1 takes. 3179: 3096:, Yde Venema, Scott Weinstein (2007). 2858:) it is the case that there exists an 1922:{\displaystyle B=Attr_{1-i}(W'_{1-i})} 2928: 2551:{\displaystyle W_{i},W_{1-i}:=V,\{\}} 484:is the priority assignment function. 3137:Automata, Logics, and Infinite Games 2966: 2964: 443:{\displaystyle E\subseteq V\times V} 107:Unsolved problem in computer science 3084:Erich Grädel, Phokion G. Kolaitis, 2264:{\displaystyle W_{0},W_{1}:=V,\{\}} 13: 3129: 1441:infinitely often is won by player 1374:be the set of nodes with priority 1343: 1054: 928: 826: 457: 302: 14: 3208: 3157: 2992: 2961: 2689: 2429: 2015:{\displaystyle W''_{i},W''_{1-i}} 1954: 1469: 1166:{\displaystyle Attr_{i}(U)^{j+1}} 411:{\displaystyle V=V_{0}\cup V_{1}} 194:{\displaystyle V=V_{0}\cup V_{1}} 100: 3197:Quasi-polynomial time algorithms 1963:{\displaystyle G''=G\setminus B} 2866:, and no node with color 2 2839:, yet finitely many have color 2313:{\displaystyle i:=p{\bmod {2}}} 1665:can only decide to escape from 1559:{\displaystyle W'_{i},W'_{1-i}} 1478:{\displaystyle G'=G\setminus A} 1270:{\displaystyle Attr_{i}(U)^{j}} 1218:{\displaystyle Attr_{i}(U)^{j}} 450:is the total set of edges, and 3058: 3041:Information Processing Letters 3025: 2983: 2922: 2910: 2695: 2683: 2617: 2595: 2435: 2423: 2363:{\displaystyle A:=Attr_{i}(U)} 2357: 2351: 2166: 2160: 1916: 1894: 1416: 1410: 1352: 1346: 1314:{\displaystyle i=p{\bmod {2}}} 1258: 1251: 1206: 1199: 1148: 1141: 1085: 1078: 1028: 1022: 987: 980: 943: 931: 885: 878: 841: 829: 792: 785: 744: 737: 695: 688: 642: 636: 585: 579: 466: 305: 261: 89:of such games was proven. The 1: 3153:, TCS, 200(1-2):135-183, 1998 3139:, Springer LNCS 2500 (2003), 3053:10.1016/S0020-0190(98)00150-1 3018:10.1016/S0304-3975(98)00009-7 2904: 2488:{\displaystyle W_{1-i}'=\{\}} 2182: := maximal priority in 2058:{\displaystyle W_{i}=W''_{i}} 1422:{\displaystyle A=Attr_{i}(U)} 136:and co-UP, as well as in QP ( 2862:and a node with color 2 2856:strongly connected component 2827:belongs to the color set of 2811:. The modified game has the 506:{\displaystyle U\subseteq V} 91:Knaster–Tarski theorem 7: 1933:to obtain the smaller game 1285:be the largest one and let 648:{\displaystyle Attr_{i}(U)} 591:{\displaystyle Attr_{i}(U)} 10: 3213: 3032:Marcin Jurdziński (1998), 2813:Rabin acceptance condition 553:is the least set of nodes 418:is the set of all nodes, 205:colored with colors from 3187:Game theory game classes 3047:(3), Elsevier: 119–124, 2172:{\displaystyle solve(G)} 1837:{\displaystyle W'_{1-i}} 1797:{\displaystyle W'_{1-i}} 1735:{\displaystyle W'_{1-i}} 1595:{\displaystyle W'_{1-i}} 318:be a parity game, where 1628:{\displaystyle W_{1-i}} 1115:. Then, for each step ( 54:, and are consequently 31:is played on a colored 2886: 2794: 2702: 2624: 2552: 2489: 2442: 2364: 2314: 2265: 2208: 2173: 2120: 2059: 2016: 1964: 1923: 1838: 1798: 1762: 1736: 1689: 1688:{\displaystyle W_{i}'} 1659: 1629: 1596: 1560: 1508: 1479: 1423: 1368: 1315: 1271: 1219: 1167: 1102: 1058: 649: 592: 539: 513:be a set of nodes and 507: 478: 444: 412: 366: 339: 312: 234: 195: 24: 2929:Rabin, M. O. (1969). 2884: 2795: 2703: 2625: 2553: 2490: 2443: 2365: 2315: 2266: 2209: 2174: 2121: 2060: 2017: 1965: 1924: 1839: 1799: 1763: 1737: 1690: 1660: 1630: 1602:is empty, then so is 1597: 1561: 1509: 1480: 1424: 1369: 1316: 1272: 1220: 1168: 1103: 1038: 650: 606:can force a visit to 593: 540: 538:{\displaystyle i=0,1} 508: 479: 445: 413: 367: 365:{\displaystyle V_{1}} 340: 338:{\displaystyle V_{0}} 313: 235: 233:{\displaystyle V_{0}} 196: 22: 2999:Zielonka, W (1998). 2714: 2633: 2561: 2501: 2454: 2373: 2323: 2288: 2220: 2192: 2142: 2069: 2026: 1974: 1937: 1860: 1812: 1772: 1746: 1710: 1669: 1643: 1606: 1570: 1518: 1493: 1452: 1382: 1325: 1289: 1229: 1177: 1119: 662: 614: 557: 517: 491: 454: 422: 376: 349: 322: 252: 217: 159: 138:quasipolynomial time 71:monadic second-order 3192:Finite model theory 3167:PGSolver Collection 3149:W. Zielonka : 2783: 2761: 2664: 2648: 2616: 2475: 2404: 2388: 2207:{\displaystyle p=0} 2109: 2054: 2011: 1989: 1929:and remove it from 1915: 1833: 1808:cannot escape from 1793: 1761:{\displaystyle 1-i} 1731: 1684: 1658:{\displaystyle 1-i} 1591: 1555: 1533: 610:from every node in 3005:Theor. Comput. Sci 2887: 2870: + 1... 2790: 2765: 2749: 2698: 2652: 2636: 2620: 2598: 2548: 2485: 2457: 2438: 2392: 2376: 2360: 2310: 2277: := nodes in 2261: 2204: 2169: 2116: 2091: 2055: 2042: 2022:. It follows that 2012: 1993: 1977: 1960: 1919: 1897: 1834: 1815: 1794: 1775: 1758: 1732: 1713: 1685: 1672: 1655: 1625: 1592: 1573: 1556: 1537: 1521: 1507:{\displaystyle G'} 1504: 1475: 1448:Consider the game 1419: 1364: 1311: 1267: 1215: 1163: 1098: 1096: 645: 588: 535: 503: 474: 440: 408: 362: 335: 308: 230: 191: 25: 3107:978-3-540-00428-8 1639:, because player 545:be a player. The 132:, more precisely 43:, called a play. 3204: 3125: 3119: 3111: 3088:, Maarten Marx, 3077: 3076: 3071: 3062: 3056: 3055: 3038: 3029: 3023: 3022: 3020: 3011:(1–2): 135–183. 2996: 2990: 2987: 2981: 2968: 2959: 2958: 2926: 2920: 2914: 2895:modal μ-calculus 2893:problem for the 2799: 2797: 2796: 2791: 2779: 2757: 2745: 2744: 2726: 2725: 2707: 2705: 2704: 2699: 2660: 2644: 2629: 2627: 2626: 2621: 2612: 2594: 2593: 2557: 2555: 2554: 2549: 2532: 2531: 2513: 2512: 2494: 2492: 2491: 2486: 2471: 2447: 2445: 2444: 2439: 2400: 2384: 2369: 2367: 2366: 2361: 2350: 2349: 2319: 2317: 2316: 2311: 2309: 2308: 2284: 2280: 2276: 2270: 2268: 2267: 2262: 2245: 2244: 2232: 2231: 2213: 2211: 2210: 2205: 2185: 2181: 2178: 2176: 2175: 2170: 2125: 2123: 2122: 2117: 2105: 2087: 2086: 2064: 2062: 2061: 2056: 2050: 2038: 2037: 2021: 2019: 2018: 2013: 2007: 1985: 1969: 1967: 1966: 1961: 1947: 1932: 1928: 1926: 1925: 1920: 1911: 1893: 1892: 1855: 1851: 1847: 1843: 1841: 1840: 1835: 1829: 1807: 1803: 1801: 1800: 1795: 1789: 1767: 1765: 1764: 1759: 1741: 1739: 1738: 1733: 1727: 1702: 1698: 1694: 1692: 1691: 1686: 1680: 1664: 1662: 1661: 1656: 1638: 1634: 1632: 1631: 1626: 1624: 1623: 1601: 1599: 1598: 1593: 1587: 1565: 1563: 1562: 1557: 1551: 1529: 1513: 1511: 1510: 1505: 1503: 1488: 1484: 1482: 1481: 1476: 1462: 1444: 1440: 1436: 1432: 1428: 1426: 1425: 1420: 1409: 1408: 1377: 1373: 1371: 1370: 1365: 1320: 1318: 1317: 1312: 1310: 1309: 1284: 1276: 1274: 1273: 1268: 1266: 1265: 1250: 1249: 1224: 1222: 1221: 1216: 1214: 1213: 1198: 1197: 1172: 1170: 1169: 1164: 1162: 1161: 1140: 1139: 1114: 1107: 1105: 1104: 1099: 1097: 1093: 1092: 1077: 1076: 1057: 1052: 1021: 1020: 995: 994: 979: 978: 924: 923: 893: 892: 877: 876: 822: 821: 800: 799: 784: 783: 758: 757: 736: 735: 703: 702: 687: 686: 654: 652: 651: 646: 635: 634: 609: 605: 601: 597: 595: 594: 589: 578: 577: 552: 548: 544: 542: 541: 536: 512: 510: 509: 504: 483: 481: 480: 475: 473: 449: 447: 446: 441: 417: 415: 414: 409: 407: 406: 394: 393: 371: 369: 368: 363: 361: 360: 344: 342: 341: 336: 334: 333: 317: 315: 314: 309: 292: 291: 279: 278: 239: 237: 236: 231: 229: 228: 200: 198: 197: 192: 190: 189: 177: 176: 108: 3212: 3211: 3207: 3206: 3205: 3203: 3202: 3201: 3177: 3176: 3160: 3132: 3130:Further reading 3113: 3112: 3108: 3080: 3069: 3063: 3059: 3036: 3030: 3026: 2997: 2993: 2988: 2984: 2969: 2962: 2947:10.2307/1995086 2927: 2923: 2915: 2911: 2907: 2879: 2853: 2805: 2800: 2769: 2753: 2734: 2730: 2721: 2717: 2715: 2712: 2711: 2656: 2640: 2634: 2631: 2630: 2602: 2583: 2579: 2562: 2559: 2558: 2521: 2517: 2508: 2504: 2502: 2499: 2498: 2461: 2455: 2452: 2451: 2396: 2380: 2374: 2371: 2370: 2345: 2341: 2324: 2321: 2320: 2304: 2300: 2289: 2286: 2285: 2282: 2278: 2274: 2240: 2236: 2227: 2223: 2221: 2218: 2217: 2193: 2190: 2189: 2183: 2179: 2143: 2140: 2139: 2095: 2076: 2072: 2070: 2067: 2066: 2046: 2033: 2029: 2027: 2024: 2023: 1997: 1981: 1975: 1972: 1971: 1940: 1938: 1935: 1934: 1930: 1901: 1882: 1878: 1861: 1858: 1857: 1853: 1849: 1845: 1819: 1813: 1810: 1809: 1805: 1779: 1773: 1770: 1769: 1747: 1744: 1743: 1717: 1711: 1708: 1707: 1700: 1696: 1676: 1670: 1667: 1666: 1644: 1641: 1640: 1636: 1613: 1609: 1607: 1604: 1603: 1577: 1571: 1568: 1567: 1541: 1525: 1519: 1516: 1515: 1496: 1494: 1491: 1490: 1486: 1455: 1453: 1450: 1449: 1442: 1438: 1434: 1430: 1404: 1400: 1383: 1380: 1379: 1375: 1326: 1323: 1322: 1305: 1301: 1290: 1287: 1286: 1282: 1261: 1257: 1245: 1241: 1230: 1227: 1226: 1209: 1205: 1193: 1189: 1178: 1175: 1174: 1151: 1147: 1135: 1131: 1120: 1117: 1116: 1112: 1095: 1094: 1088: 1084: 1072: 1068: 1053: 1042: 1031: 1016: 1012: 1000: 999: 990: 986: 974: 970: 913: 909: 888: 884: 872: 868: 817: 813: 795: 791: 779: 775: 759: 747: 743: 731: 727: 715: 714: 704: 698: 694: 682: 678: 665: 663: 660: 659: 630: 626: 615: 612: 611: 607: 603: 599: 573: 569: 558: 555: 554: 550: 546: 518: 515: 514: 492: 489: 488: 469: 455: 452: 451: 423: 420: 419: 402: 398: 389: 385: 377: 374: 373: 356: 352: 350: 347: 346: 329: 325: 323: 320: 319: 287: 283: 274: 270: 253: 250: 249: 246: 224: 220: 218: 215: 214: 185: 181: 172: 168: 160: 157: 156: 149:bipartite graph 119: 118: 113: 110: 103: 52:Borel hierarchy 37:natural numbers 17: 12: 11: 5: 3210: 3200: 3199: 3194: 3189: 3175: 3174: 3169: 3159: 3158:External links 3156: 3155: 3154: 3147: 3131: 3128: 3127: 3126: 3106: 3094:Moshe Y. Vardi 3079: 3078: 3057: 3024: 2991: 2982: 2960: 2921: 2908: 2906: 2903: 2891:model-checking 2878: 2875: 2851: 2804: 2801: 2789: 2786: 2782: 2778: 2775: 2772: 2768: 2764: 2760: 2756: 2752: 2748: 2743: 2740: 2737: 2733: 2729: 2724: 2720: 2697: 2694: 2691: 2688: 2685: 2682: 2679: 2676: 2673: 2670: 2667: 2663: 2659: 2655: 2651: 2647: 2643: 2639: 2619: 2615: 2611: 2608: 2605: 2601: 2597: 2592: 2589: 2586: 2582: 2578: 2575: 2572: 2569: 2566: 2547: 2544: 2541: 2538: 2535: 2530: 2527: 2524: 2520: 2516: 2511: 2507: 2484: 2481: 2478: 2474: 2470: 2467: 2464: 2460: 2437: 2434: 2431: 2428: 2425: 2422: 2419: 2416: 2413: 2410: 2407: 2403: 2399: 2395: 2391: 2387: 2383: 2379: 2359: 2356: 2353: 2348: 2344: 2340: 2337: 2334: 2331: 2328: 2307: 2303: 2299: 2296: 2293: 2281:with priority 2260: 2257: 2254: 2251: 2248: 2243: 2239: 2235: 2230: 2226: 2203: 2200: 2197: 2168: 2165: 2162: 2159: 2156: 2153: 2150: 2147: 2135: 2115: 2112: 2108: 2104: 2101: 2098: 2094: 2090: 2085: 2082: 2079: 2075: 2053: 2049: 2045: 2041: 2036: 2032: 2010: 2006: 2003: 2000: 1996: 1992: 1988: 1984: 1980: 1959: 1956: 1953: 1950: 1946: 1943: 1918: 1914: 1910: 1907: 1904: 1900: 1896: 1891: 1888: 1885: 1881: 1877: 1874: 1871: 1868: 1865: 1832: 1828: 1825: 1822: 1818: 1792: 1788: 1785: 1782: 1778: 1757: 1754: 1751: 1730: 1726: 1723: 1720: 1716: 1706:Otherwise, if 1683: 1679: 1675: 1654: 1651: 1648: 1622: 1619: 1616: 1612: 1590: 1586: 1583: 1580: 1576: 1554: 1550: 1547: 1544: 1540: 1536: 1532: 1528: 1524: 1502: 1499: 1474: 1471: 1468: 1465: 1461: 1458: 1418: 1415: 1412: 1407: 1403: 1399: 1396: 1393: 1390: 1387: 1363: 1360: 1357: 1354: 1351: 1348: 1345: 1342: 1339: 1336: 1333: 1330: 1308: 1304: 1300: 1297: 1294: 1264: 1260: 1256: 1253: 1248: 1244: 1240: 1237: 1234: 1212: 1208: 1204: 1201: 1196: 1192: 1188: 1185: 1182: 1160: 1157: 1154: 1150: 1146: 1143: 1138: 1134: 1130: 1127: 1124: 1109: 1108: 1091: 1087: 1083: 1080: 1075: 1071: 1067: 1064: 1061: 1056: 1051: 1048: 1045: 1041: 1037: 1034: 1032: 1030: 1027: 1024: 1019: 1015: 1011: 1008: 1005: 1002: 1001: 998: 993: 989: 985: 982: 977: 973: 969: 966: 963: 960: 957: 954: 951: 948: 945: 942: 939: 936: 933: 930: 927: 922: 919: 916: 912: 908: 905: 902: 899: 896: 891: 887: 883: 880: 875: 871: 867: 864: 861: 858: 855: 852: 849: 846: 843: 840: 837: 834: 831: 828: 825: 820: 816: 812: 809: 806: 803: 798: 794: 790: 787: 782: 778: 774: 771: 768: 765: 762: 760: 756: 753: 750: 746: 742: 739: 734: 730: 726: 723: 720: 717: 716: 713: 710: 707: 705: 701: 697: 693: 690: 685: 681: 677: 674: 671: 668: 667: 644: 641: 638: 633: 629: 625: 622: 619: 587: 584: 581: 576: 572: 568: 565: 562: 549:-attractor of 534: 531: 528: 525: 522: 502: 499: 496: 472: 468: 465: 462: 459: 439: 436: 433: 430: 427: 405: 401: 397: 392: 388: 384: 381: 359: 355: 332: 328: 307: 304: 301: 298: 295: 290: 286: 282: 277: 273: 269: 266: 263: 260: 257: 245: 242: 227: 223: 188: 184: 180: 175: 171: 167: 164: 114: 111: 105: 102: 101:Solving a game 99: 33:directed graph 15: 9: 6: 4: 3: 2: 3209: 3198: 3195: 3193: 3190: 3188: 3185: 3184: 3182: 3173: 3170: 3168: 3165: 3164: 3163: 3152: 3148: 3146: 3145:3-540-00388-6 3142: 3138: 3134: 3133: 3123: 3117: 3109: 3103: 3099: 3095: 3091: 3087: 3086:Leonid Libkin 3082: 3081: 3075: 3068: 3061: 3054: 3050: 3046: 3042: 3035: 3028: 3019: 3014: 3010: 3006: 3002: 2995: 2986: 2980: 2979:0-8186-2445-0 2976: 2972: 2971:E. A. Emerson 2967: 2965: 2956: 2952: 2948: 2944: 2940: 2936: 2932: 2925: 2918: 2913: 2909: 2902: 2900: 2896: 2892: 2883: 2874: 2871: 2869: 2865: 2861: 2857: 2850: 2844: 2842: 2838: 2834: 2830: 2826: 2823:if the color 2822: 2818: 2814: 2810: 2787: 2784: 2780: 2776: 2773: 2770: 2766: 2762: 2758: 2754: 2750: 2746: 2741: 2738: 2735: 2731: 2727: 2722: 2718: 2710: 2692: 2686: 2680: 2677: 2674: 2671: 2668: 2665: 2661: 2657: 2653: 2649: 2645: 2641: 2637: 2613: 2609: 2606: 2603: 2599: 2590: 2587: 2584: 2580: 2576: 2573: 2570: 2567: 2564: 2539: 2536: 2533: 2528: 2525: 2522: 2518: 2514: 2509: 2505: 2497: 2476: 2472: 2468: 2465: 2462: 2458: 2450: 2432: 2426: 2420: 2417: 2414: 2411: 2408: 2405: 2401: 2397: 2393: 2389: 2385: 2381: 2377: 2354: 2346: 2342: 2338: 2335: 2332: 2329: 2326: 2305: 2297: 2294: 2291: 2273: 2252: 2249: 2246: 2241: 2237: 2233: 2228: 2224: 2216: 2201: 2198: 2195: 2188: 2163: 2157: 2154: 2151: 2148: 2145: 2138: 2134: 2132: 2127: 2113: 2110: 2106: 2102: 2099: 2096: 2092: 2088: 2083: 2080: 2077: 2073: 2051: 2047: 2043: 2039: 2034: 2030: 2008: 2004: 2001: 1998: 1994: 1990: 1986: 1982: 1978: 1957: 1951: 1948: 1944: 1941: 1912: 1908: 1905: 1902: 1898: 1889: 1886: 1883: 1879: 1875: 1872: 1869: 1866: 1863: 1830: 1826: 1823: 1820: 1816: 1790: 1786: 1783: 1780: 1776: 1755: 1752: 1749: 1728: 1724: 1721: 1718: 1714: 1704: 1681: 1677: 1673: 1652: 1649: 1646: 1635:for the game 1620: 1617: 1614: 1610: 1588: 1584: 1581: 1578: 1574: 1552: 1548: 1545: 1542: 1538: 1534: 1530: 1526: 1522: 1500: 1497: 1472: 1466: 1463: 1459: 1456: 1446: 1413: 1405: 1401: 1397: 1394: 1391: 1388: 1385: 1358: 1355: 1349: 1340: 1337: 1331: 1328: 1306: 1298: 1295: 1292: 1278: 1262: 1254: 1246: 1242: 1238: 1235: 1232: 1210: 1202: 1194: 1190: 1186: 1183: 1180: 1158: 1155: 1152: 1144: 1136: 1132: 1128: 1125: 1122: 1089: 1081: 1073: 1069: 1065: 1062: 1059: 1049: 1046: 1043: 1039: 1035: 1033: 1025: 1017: 1013: 1009: 1006: 1003: 991: 983: 975: 971: 967: 964: 961: 958: 955: 952: 949: 946: 940: 937: 934: 925: 920: 917: 914: 910: 906: 903: 897: 889: 881: 873: 869: 865: 862: 859: 856: 853: 850: 847: 844: 838: 835: 832: 823: 818: 814: 810: 807: 801: 796: 788: 780: 776: 772: 769: 766: 763: 761: 754: 751: 748: 740: 732: 728: 724: 721: 718: 711: 708: 706: 699: 691: 683: 679: 675: 672: 669: 658: 657: 656: 639: 631: 627: 623: 620: 617: 582: 574: 570: 566: 563: 560: 532: 529: 526: 523: 520: 500: 497: 494: 485: 463: 460: 437: 434: 431: 428: 425: 403: 399: 395: 390: 386: 382: 379: 357: 353: 330: 326: 299: 296: 293: 288: 284: 280: 275: 271: 267: 264: 258: 255: 241: 225: 221: 212: 208: 204: 186: 182: 178: 173: 169: 165: 162: 154: 150: 145: 143: 139: 135: 131: 127: 123: 117: 98: 94: 92: 88: 84: 80: 76: 72: 68: 64: 59: 57: 53: 48: 44: 42: 38: 34: 30: 21: 3161: 3150: 3136: 3100:. Springer. 3097: 3090:Joel Spencer 3073: 3060: 3044: 3040: 3027: 3008: 3004: 2994: 2985: 2938: 2934: 2924: 2917:D. A. Martin 2912: 2899:modal logics 2888: 2872: 2867: 2863: 2859: 2848: 2845: 2840: 2836: 2832: 2828: 2824: 2820: 2816: 2806: 2708: 2495: 2448: 2271: 2214: 2186: 2136: 2128: 1705: 1447: 1279: 1110: 486: 247: 210: 206: 202: 152: 146: 121: 120: 95: 85:= 2), where 82: 77:successors ( 74: 67:decidability 65:'s proof of 60: 49: 45: 28: 26: 1768:can win on 598:containing 87:determinacy 29:parity game 3181:Categories 2905:References 2819:has color 2131:pseudocode 2129:In simple 1804:as player 602:such that 73:theory of 56:determined 3116:cite book 3074:Stoc 2017 2785:∪ 2774:− 2739:− 2690:∖ 2607:− 2588:− 2526:− 2466:− 2430:∖ 2111:∪ 2100:− 2081:− 2002:− 1955:∖ 1906:− 1887:− 1824:− 1784:− 1753:− 1722:− 1650:− 1618:− 1582:− 1546:− 1470:∖ 1433:. Player 1344:Ω 1341:∣ 1055:∞ 1040:⋃ 959:∈ 947:∈ 929:∀ 926:∣ 918:− 907:∈ 898:∪ 857:∈ 845:∈ 827:∃ 824:∣ 811:∈ 802:∪ 498:⊆ 467:→ 458:Ω 435:× 429:⊆ 396:∪ 303:Ω 179:∪ 155:vertices 2781:″ 2759:″ 2662:″ 2646:″ 2614:′ 2473:′ 2402:′ 2386:′ 2137:function 2107:″ 2052:″ 2009:″ 1987:″ 1945:″ 1913:′ 1831:′ 1791:′ 1729:′ 1682:′ 1589:′ 1553:′ 1531:′ 1501:′ 1460:′ 1378:and let 2955:1995086 2809:NP-hard 1848:(since 122:Solving 69:of the 3143:  3104:  2977:  2953:  2709:return 2496:return 2215:return 1852:is an 345:resp. 201:, and 3070:(PDF) 3037:(PDF) 2951:JSTOR 1566:. If 151:with 142:PTime 130:co-NP 63:Rabin 3172:Oink 3141:ISBN 3122:link 3102:ISBN 2975:ISBN 2841:2i+1 2272:else 2065:and 128:and 81:for 41:path 3049:doi 3013:doi 3009:200 2943:doi 2939:141 2302:mod 1844:to 1695:to 1303:mod 209:to 79:S2S 3183:: 3118:}} 3114:{{ 3092:, 3072:, 3045:68 3043:, 3039:, 3007:. 3003:. 2963:^ 2949:. 2937:. 2933:. 2843:. 2837:2i 2747::= 2666::= 2568::= 2534::= 2449:if 2406::= 2330::= 2295::= 2247::= 2187:if 2126:. 1703:. 1445:. 1036::= 764::= 709::= 144:. 134:UP 126:NP 58:. 27:A 3124:) 3110:. 3051:: 3021:. 3015:: 2957:. 2945:: 2868:i 2864:i 2860:i 2852:0 2849:V 2833:i 2829:v 2825:j 2821:j 2817:v 2788:B 2777:i 2771:1 2767:W 2763:, 2755:i 2751:W 2742:i 2736:1 2732:W 2728:, 2723:i 2719:W 2696:) 2693:B 2687:G 2684:( 2681:e 2678:v 2675:l 2672:o 2669:s 2658:1 2654:W 2650:, 2642:0 2638:W 2618:) 2610:i 2604:1 2600:W 2596:( 2591:i 2585:1 2581:r 2577:t 2574:t 2571:A 2565:B 2546:} 2543:{ 2540:, 2537:V 2529:i 2523:1 2519:W 2515:, 2510:i 2506:W 2483:} 2480:{ 2477:= 2469:i 2463:1 2459:W 2436:) 2433:A 2427:G 2424:( 2421:e 2418:v 2415:l 2412:o 2409:s 2398:1 2394:W 2390:, 2382:0 2378:W 2358:) 2355:U 2352:( 2347:i 2343:r 2339:t 2336:t 2333:A 2327:A 2306:2 2298:p 2292:i 2283:p 2279:G 2275:U 2259:} 2256:{ 2253:, 2250:V 2242:1 2238:W 2234:, 2229:0 2225:W 2202:0 2199:= 2196:p 2184:G 2180:p 2167:) 2164:G 2161:( 2158:e 2155:v 2152:l 2149:o 2146:s 2114:B 2103:i 2097:1 2093:W 2089:= 2084:i 2078:1 2074:W 2048:i 2044:W 2040:= 2035:i 2031:W 2005:i 1999:1 1995:W 1991:, 1983:i 1979:W 1958:B 1952:G 1949:= 1942:G 1931:G 1917:) 1909:i 1903:1 1899:W 1895:( 1890:i 1884:1 1880:r 1876:t 1873:t 1870:A 1867:= 1864:B 1854:i 1850:A 1846:A 1827:i 1821:1 1817:W 1806:i 1787:i 1781:1 1777:W 1756:i 1750:1 1725:i 1719:1 1715:W 1701:i 1697:A 1678:i 1674:W 1653:i 1647:1 1637:G 1621:i 1615:1 1611:W 1585:i 1579:1 1575:W 1549:i 1543:1 1539:W 1535:, 1527:i 1523:W 1498:G 1487:A 1473:A 1467:G 1464:= 1457:G 1443:i 1439:A 1435:i 1431:i 1417:) 1414:U 1411:( 1406:i 1402:r 1398:t 1395:t 1392:A 1389:= 1386:A 1376:p 1362:} 1359:p 1356:= 1353:) 1350:v 1347:( 1338:v 1335:{ 1332:= 1329:U 1307:2 1299:p 1296:= 1293:i 1283:p 1263:j 1259:) 1255:U 1252:( 1247:i 1243:r 1239:t 1236:t 1233:A 1211:j 1207:) 1203:U 1200:( 1195:i 1191:r 1187:t 1184:t 1181:A 1159:1 1156:+ 1153:j 1149:) 1145:U 1142:( 1137:i 1133:r 1129:t 1126:t 1123:A 1113:U 1090:j 1086:) 1082:U 1079:( 1074:i 1070:r 1066:t 1063:t 1060:A 1050:0 1047:= 1044:j 1029:) 1026:U 1023:( 1018:i 1014:r 1010:t 1007:t 1004:A 997:} 992:j 988:) 984:U 981:( 976:i 972:r 968:t 965:t 962:A 956:w 953:: 950:E 944:) 941:w 938:, 935:v 932:( 921:i 915:1 911:V 904:v 901:{ 895:} 890:j 886:) 882:U 879:( 874:i 870:r 866:t 863:t 860:A 854:w 851:: 848:E 842:) 839:w 836:, 833:v 830:( 819:i 815:V 808:v 805:{ 797:j 793:) 789:U 786:( 781:i 777:r 773:t 770:t 767:A 755:1 752:+ 749:j 745:) 741:U 738:( 733:i 729:r 725:t 722:t 719:A 712:U 700:0 696:) 692:U 689:( 684:i 680:r 676:t 673:t 670:A 643:) 640:U 637:( 632:i 628:r 624:t 621:t 618:A 608:U 604:i 600:U 586:) 583:U 580:( 575:i 571:r 567:t 564:t 561:A 551:U 547:i 533:1 530:, 527:0 524:= 521:i 501:V 495:U 471:N 464:V 461:: 438:V 432:V 426:E 404:1 400:V 391:0 387:V 383:= 380:V 358:1 354:V 331:0 327:V 306:) 300:, 297:E 294:, 289:1 285:V 281:, 276:0 272:V 268:, 265:V 262:( 259:= 256:G 226:0 222:V 211:m 207:1 203:V 187:1 183:V 174:0 170:V 166:= 163:V 153:n 109:: 83:n 75:n

Index


directed graph
natural numbers
path
Borel hierarchy
determined
Rabin
decidability
monadic second-order
S2S
determinacy
Knaster–Tarski theorem
(more unsolved problems in computer science)
NP
co-NP
UP
quasipolynomial time
PTime
bipartite graph
pseudocode
NP-hard
Rabin acceptance condition
strongly connected component

model-checking
modal μ-calculus
modal logics
D. A. Martin
"Decidability of second-order theories and automata on infinite trees"
doi

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