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Probabilistic method

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Alternatively, the probabilistic method can also be used to guarantee the existence of a desired element in a sample space with a value that is greater than or equal to the calculated expected value, since the non-existence of such element would imply every element in the sample space is less than
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This result gives a hint as to why the computation of the chromatic number of a graph is so difficult: even when there are no local reasons (such as small cycles) for a graph to require many colors the chromatic number can still be arbitrarily large.
2339:{\displaystyle \Pr \left(X>{\tfrac {n}{2}}\right)\leq {\frac {2}{n}}E\leq {\frac {1}{n}}\sum _{i=3}^{g-1}p^{i}n^{i}={\frac {1}{n}}\sum _{i=3}^{g-1}n^{\frac {i}{g}}\leq {\frac {g}{n}}n^{\frac {g-1}{g}}=gn^{-{\frac {1}{g}}}=o(1).} 2432: 2056: 1004: 2735:, the probability that a graph from the distribution has both properties is positive, as the events for these properties cannot be disjoint (if they were, their probabilities would sum up to more than 1). 2840: 2717: 1642: 1650: 1303: 1146: 119:. If it can be shown that the random variable can take on a value less than the expected value, this proves that the random variable can also take on some value greater than the expected value. 2409: 666: 2995: 158:), many of the most well known proofs using this method are due to Erdős. The first example below describes one such result from 1947 that gives a proof of a lower bound for the 3071:
Elishakoff I., Lin Y.K. and Zhu L.P., Probabilistic and Convex Modeling of Acoustically Excited Structures, Elsevier Science Publishers, Amsterdam, 1994, VIII + pp. 296;
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If every object in a collection of objects fails to have a certain property, then the probability that a random object chosen from the collection has that property is zero.
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Elishakoff I., Probabilistic Methods in the Theory of Structures: Random Strength of Materials, Random Vibration, and Buckling, World Scientific, Singapore,
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that the result is of the prescribed kind is strictly greater than zero. Although the proof uses probability, the final conclusion is determined for
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the existence of a prescribed kind of mathematical object. It works by showing that if one randomly chooses objects from a specified class, the
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Of these colorings, only 2 colorings are 'bad' for that subgraph (the colorings in which all vertices are red or all vertices are blue).
1832:{\displaystyle 2{n \choose r}2^{{n \choose 2}-{r \choose 2}}<2^{n \choose 2}\Leftrightarrow {n \choose r}2^{1-{r \choose 2}}<1} 2672: 1551: 3048: 2805: 3065: 1197: 3044: 104:
Similarly, showing that the probability is (strictly) less than 1 can be used to prove the existence of an object that does
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Hence, the total number of colorings that are bad for some (at least one) subgraph is at most
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To do so, we color the graph randomly. Color each edge independently with probability
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A 1959 paper of Erdős (see reference cited below) addressed the following problem in
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The same fact can be proved without probability, using a simple counting argument:
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via the probabilistic method (for example, Szele's 1943 result that there exist
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of being blue. We calculate the expected number of monochromatic subgraphs on
3090: 1330: 78: 70: 43: 47: 3021: 2969: 2952: 2910: 1854: 1391: 1017:), so the expectation of the sum (the expected number of all monochromatic 1839:, there must be at least one coloring which is not 'bad' for any subgraph. 2051:{\displaystyle {\frac {n!}{2\cdot i\cdot (n-i)!}}\leq {\frac {n^{i}}{2}}} 66: 55: 31: 999:{\displaystyle \sum _{i=1}^{C(n,r)}E={n \choose r}2^{1-{r \choose 2}}.} 215:
vertices which is monochromatic (every edge colored the same color).
1322:), there must exist a coloring in which there are no monochromatic 111:
Another way to use the probabilistic method is by calculating the
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in two colors (say red and blue) so that there is no complete
2712:{\displaystyle y=\left\lceil {\frac {n}{2k}}\right\rceil \!.} 1637:{\displaystyle 2{n \choose r}2^{{n \choose 2}-{r \choose 2}}} 2852:
independent sets, and, hence, has chromatic number at least
2835:{\displaystyle \left\lceil {\frac {n'}{k}}\right\rceil } 1298:{\displaystyle E={n \choose r}2^{1-{r \choose 2}}<1} 1009:
The sum of expectations is the expectation of the sum (
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vertices that contains only cycles of length at least
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Common tools used in the probabilistic method include
2808: 2765: 2675: 2435: 2377: 2084: 1983: 1653: 1554: 1504: 1465: 1419: 1200: 1175:-subgraphs in this random coloring is a non-negative 1046: 1023: 863: 828: 778: 743: 719: 684: 583: 548: 513: 472: 436: 409: 370: 350: 326: 286: 266: 239: 2867: 2723:, property 2 holds with a probability of more than 2352:, property 1 holds with a probability of more than 1378:A weakness of this argument is that it is entirely 1141:{\displaystyle E={n \choose r}2^{1-{r \choose 2}}.} 65:This method has now been applied to other areas of 2906:Probabilistic proofs of non-probabilistic theorems 2834: 2790: 2711: 2655: 2403: 2338: 2050: 1831: 1636: 1534: 1490: 1444: 1297: 1140: 1029: 998: 846: 814: 764: 725: 705: 660: 566: 534: 499: 454: 422: 392: 356: 332: 308: 272: 252: 2705: 2473: 2460: 1892:It can be shown that such a graph exists for any 1782: 1769: 1673: 1660: 1574: 1561: 1482: 1469: 1436: 1423: 1248: 1235: 1151:Consider what happens if this value is less than 1094: 1081: 952: 939: 344:otherwise. Note that the number of monochromatic 3088: 2742:has these two properties, we can remove at most 2436: 2085: 2422:be the size of the largest independent set in 2404:{\displaystyle \lceil {\tfrac {n}{2k}}\rceil } 675:comes because there are two possible colors). 195:. We wish to show (for small enough values of 27:Nonconstructive method for mathematical proofs 1815: 1802: 1756: 1743: 1725: 1712: 1700: 1687: 1626: 1613: 1601: 1588: 1525: 1512: 1281: 1268: 1155:. Since the expected number of monochromatic 1127: 1114: 985: 972: 650: 637: 280:vertices from our graph, define the variable 2398: 2378: 713:possible subsets we could have chosen, i.e. 141: 1926:. We show that with positive probability, 1900:, and the proof is reasonably simple. Let 1187:is the only non-negative integer less than 661:{\displaystyle E=2\cdot 2^{-{r \choose 2}}} 1904:be very large and consider a random graph 507:is simply the probability that all of the 3011: 2993: 2968: 2950: 1962:be the number cycles of length less than 3056:Extremal and Probabilistic Combinatorics 1930:satisfies the following two properties: 2939:(2ed). New York: Wiley-Interscience. 2916: 14: 3089: 2935:Alon, Noga; Spencer, Joel H. (2000). 2923:Probabilistic Methods in Combinatorics 2848:can only be partitioned into at least 123:the expected value, a contradiction. 3054:Alon, N and Krivelevich, M (2006). 2901:Method of conditional probabilities 1386:vertices contains no monochromatic 199:) that it is possible to color the 108:satisfy the prescribed properties. 24: 2996:"Graph theory and probability, II" 2464: 1806: 1773: 1747: 1716: 1691: 1664: 1617: 1592: 1565: 1516: 1473: 1427: 1272: 1239: 1118: 1085: 976: 943: 641: 146:Although others before him proved 25: 3118: 1966:. The number of cycles of length 1848: 1498:edges and thus can be colored in 1167:-subgraphs is strictly less than 1159:-subgraphs is strictly less than 2870: 340:vertices is the same color, and 179: 2061:and each of them is present in 1535:{\displaystyle 2^{r \choose 2}} 1308:(which holds, for example, for 678:This holds true for any of the 96: 2953:"Graph theory and probability" 2647: 2641: 2630: 2600: 2565: 2553: 2513: 2501: 2492: 2479: 2451: 2439: 2330: 2324: 2138: 2132: 2019: 2007: 1912:vertices, where every edge in 1763: 1400: 1226: 1223: 1210: 1204: 1171:. The number of monochromatic 1072: 1069: 1056: 1050: 930: 927: 909: 903: 895: 883: 809: 806: 788: 782: 759: 747: 700: 688: 614: 611: 593: 587: 529: 517: 494: 476: 387: 374: 303: 290: 62:, without any possible error. 13: 1: 2929: 2719:Thus, for sufficiently large 1491:{\displaystyle {r \choose 2}} 1445:{\displaystyle {n \choose r}} 1013:of whether the variables are 772:. So we have that the sum of 154:containing a large number of 3082: 2738:Here comes the trick: since 2348:Thus for sufficiently large 500:{\displaystyle X(S_{r}^{i})} 7: 2863: 1947:cycles of length less than 1865:, does there exist a graph 18:Probabilistic combinatorics 10: 3123: 2791:{\displaystyle n'\geq n/2} 1857:: given positive integers 320:if every edge amongst the 42:method, primarily used in 1970:in the complete graph on 847:{\displaystyle S_{r}^{i}} 567:{\displaystyle S_{r}^{i}} 455:{\displaystyle S_{r}^{i}} 430:. For any individual set 364:-subgraphs is the sum of 142:Two examples due to Erdős 3049:The Probabilistic Method 2937:The probabilistic method 2896:Incompressibility method 2886:Interactive proof system 1916:exists with probability 1394:for more than 50 years. 393:{\displaystyle X(S_{r})} 309:{\displaystyle X(S_{r})} 3107:Probabilistic arguments 2731:For sufficiently large 3022:10.4153/CJM-1961-029-9 2970:10.4153/CJM-1959-003-9 2836: 2792: 2753:to obtain a new graph 2713: 2657: 2405: 2340: 2240: 2180: 2052: 1833: 1638: 1536: 1492: 1446: 1299: 1191:). It follows that if 1142: 1031: 1000: 899: 848: 816: 766: 765:{\displaystyle C(n,r)} 727: 707: 706:{\displaystyle C(n,r)} 662: 568: 536: 535:{\displaystyle C(r,2)} 501: 456: 424: 394: 358: 334: 310: 274: 254: 2837: 2793: 2714: 2658: 2406: 2341: 2214: 2154: 2053: 1834: 1639: 1537: 1493: 1447: 1329:By definition of the 1300: 1143: 1032: 1001: 864: 849: 817: 767: 728: 708: 663: 569: 537: 502: 457: 425: 423:{\displaystyle S_{r}} 395: 359: 335: 311: 275: 255: 253:{\displaystyle S_{r}} 230:vertices as follows: 2925:, MIT OpenCourseWare 2917:Additional resources 2806: 2763: 2673: 2433: 2375: 2082: 1981: 1651: 1552: 1502: 1463: 1417: 1409:The total number of 1348:must be bigger than 1333:, this implies that 1198: 1044: 1021: 861: 826: 776: 741: 717: 682: 581: 574:are the same color: 546: 511: 470: 434: 407: 368: 348: 324: 284: 264: 237: 36:probabilistic method 3102:Mathematical proofs 2891:Las Vegas algorithm 2426:. Clearly, we have 2073:Markov's inequality 1873:of length at least 1367:must grow at least 1179:, hence it must be 926: 843: 805: 610: 563: 493: 451: 128:Markov's inequality 87:randomized rounding 2994:Erdős, P. (1961). 2951:Erdős, P. (1959). 2878:Mathematics portal 2832: 2788: 2709: 2653: 2401: 2396: 2336: 2109: 2048: 1829: 1634: 1532: 1488: 1442: 1295: 1138: 1027: 996: 912: 844: 829: 812: 791: 762: 723: 703: 658: 596: 564: 549: 532: 497: 479: 452: 437: 420: 400:over all possible 390: 354: 330: 306: 270: 250: 184:Suppose we have a 156:Hamiltonian cycles 136:Lovász local lemma 91:information theory 3066:978-981-3149-84-7 2826: 2699: 2595: 2572: 2520: 2471: 2395: 2314: 2289: 2267: 2253: 2212: 2152: 2127: 2108: 2065:with probability 2046: 2026: 1940:contains at most 1869:containing only 1813: 1780: 1754: 1723: 1698: 1671: 1624: 1599: 1572: 1523: 1480: 1434: 1352:. In particular, 1279: 1246: 1125: 1092: 1030:{\displaystyle r} 983: 950: 815:{\displaystyle E} 726:{\displaystyle i} 648: 357:{\displaystyle r} 333:{\displaystyle r} 273:{\displaystyle r} 222:of being red and 46:and pioneered by 16:(Redirected from 3114: 3051:. Lecture notes. 3041: 3015: 2990: 2972: 2880: 2875: 2874: 2855: 2851: 2847: 2841: 2839: 2838: 2833: 2831: 2827: 2822: 2814: 2801: 2797: 2795: 2794: 2789: 2784: 2773: 2758: 2752: 2748: 2741: 2734: 2726: 2722: 2718: 2716: 2715: 2710: 2704: 2700: 2698: 2687: 2662: 2660: 2659: 2654: 2634: 2633: 2596: 2588: 2575: 2574: 2573: 2568: 2545: 2535: 2534: 2522: 2521: 2516: 2496: 2478: 2477: 2476: 2463: 2425: 2421: 2410: 2408: 2407: 2402: 2397: 2394: 2383: 2366: 2355: 2351: 2345: 2343: 2342: 2337: 2317: 2316: 2315: 2307: 2291: 2290: 2285: 2274: 2268: 2260: 2255: 2254: 2246: 2239: 2228: 2213: 2205: 2200: 2199: 2190: 2189: 2179: 2168: 2153: 2145: 2128: 2120: 2115: 2111: 2110: 2101: 2070: 2064: 2057: 2055: 2054: 2049: 2047: 2042: 2041: 2032: 2027: 2025: 1993: 1985: 1973: 1969: 1965: 1961: 1950: 1946: 1939: 1929: 1925: 1915: 1911: 1907: 1903: 1899: 1895: 1888: 1884: 1879:chromatic number 1877:, such that the 1876: 1868: 1864: 1860: 1842: 1838: 1836: 1835: 1830: 1822: 1821: 1820: 1819: 1818: 1805: 1787: 1786: 1785: 1772: 1762: 1761: 1760: 1759: 1746: 1732: 1731: 1730: 1729: 1728: 1715: 1705: 1704: 1703: 1690: 1678: 1677: 1676: 1663: 1643: 1641: 1640: 1635: 1633: 1632: 1631: 1630: 1629: 1616: 1606: 1605: 1604: 1591: 1579: 1578: 1577: 1564: 1541: 1539: 1538: 1533: 1531: 1530: 1529: 1528: 1515: 1497: 1495: 1494: 1489: 1487: 1486: 1485: 1472: 1451: 1449: 1448: 1443: 1441: 1440: 1439: 1426: 1404: 1389: 1385: 1374: 1366: 1351: 1347: 1325: 1321: 1314: 1304: 1302: 1301: 1296: 1288: 1287: 1286: 1285: 1284: 1271: 1253: 1252: 1251: 1238: 1222: 1221: 1190: 1186: 1182: 1174: 1170: 1166: 1162: 1158: 1154: 1147: 1145: 1144: 1139: 1134: 1133: 1132: 1131: 1130: 1117: 1099: 1098: 1097: 1084: 1068: 1067: 1036: 1034: 1033: 1028: 1005: 1003: 1002: 997: 992: 991: 990: 989: 988: 975: 957: 956: 955: 942: 925: 920: 898: 878: 853: 851: 850: 845: 842: 837: 821: 819: 818: 813: 804: 799: 771: 769: 768: 763: 736: 732: 730: 729: 724: 712: 710: 709: 704: 674: 667: 665: 664: 659: 657: 656: 655: 654: 653: 640: 609: 604: 573: 571: 570: 565: 562: 557: 541: 539: 538: 533: 506: 504: 503: 498: 492: 487: 461: 459: 458: 453: 450: 445: 429: 427: 426: 421: 419: 418: 399: 397: 396: 391: 386: 385: 363: 361: 360: 355: 343: 339: 337: 336: 331: 319: 315: 313: 312: 307: 302: 301: 279: 277: 276: 271: 259: 257: 256: 251: 249: 248: 229: 225: 221: 214: 198: 191: 175: 83:computer science 81:, as well as in 21: 3122: 3121: 3117: 3116: 3115: 3113: 3112: 3111: 3087: 3086: 3085: 3013:10.1.1.210.6669 2932: 2919: 2876: 2869: 2866: 2853: 2849: 2843: 2815: 2813: 2809: 2807: 2804: 2803: 2799: 2780: 2766: 2764: 2761: 2760: 2754: 2750: 2743: 2739: 2732: 2724: 2720: 2691: 2686: 2682: 2674: 2671: 2670: 2587: 2583: 2579: 2546: 2544: 2540: 2536: 2530: 2526: 2497: 2495: 2491: 2472: 2459: 2458: 2457: 2434: 2431: 2430: 2423: 2419: 2387: 2381: 2376: 2373: 2372: 2369:independent set 2364: 2353: 2349: 2306: 2302: 2298: 2275: 2273: 2269: 2259: 2245: 2241: 2229: 2218: 2204: 2195: 2191: 2185: 2181: 2169: 2158: 2144: 2119: 2099: 2092: 2088: 2083: 2080: 2079: 2066: 2062: 2037: 2033: 2031: 1994: 1986: 1984: 1982: 1979: 1978: 1971: 1967: 1963: 1959: 1948: 1941: 1937: 1927: 1917: 1913: 1909: 1905: 1901: 1897: 1893: 1886: 1882: 1874: 1866: 1862: 1858: 1851: 1846: 1845: 1814: 1801: 1800: 1799: 1792: 1788: 1781: 1768: 1767: 1766: 1755: 1742: 1741: 1740: 1736: 1724: 1711: 1710: 1709: 1699: 1686: 1685: 1684: 1683: 1679: 1672: 1659: 1658: 1657: 1652: 1649: 1648: 1625: 1612: 1611: 1610: 1600: 1587: 1586: 1585: 1584: 1580: 1573: 1560: 1559: 1558: 1553: 1550: 1549: 1542:different ways. 1524: 1511: 1510: 1509: 1505: 1503: 1500: 1499: 1481: 1468: 1467: 1466: 1464: 1461: 1460: 1459:-subgraphs has 1435: 1422: 1421: 1420: 1418: 1415: 1414: 1405: 1401: 1396: 1387: 1383: 1380:nonconstructive 1372: 1353: 1349: 1334: 1323: 1316: 1309: 1280: 1267: 1266: 1265: 1258: 1254: 1247: 1234: 1233: 1232: 1217: 1213: 1199: 1196: 1195: 1188: 1184: 1180: 1172: 1168: 1164: 1160: 1156: 1152: 1126: 1113: 1112: 1111: 1104: 1100: 1093: 1080: 1079: 1078: 1063: 1059: 1045: 1042: 1041: 1037:-subgraphs) is 1022: 1019: 1018: 984: 971: 970: 969: 962: 958: 951: 938: 937: 936: 921: 916: 879: 868: 862: 859: 858: 838: 833: 827: 824: 823: 800: 795: 777: 774: 773: 742: 739: 738: 734: 718: 715: 714: 683: 680: 679: 672: 671:(the factor of 649: 636: 635: 634: 630: 626: 605: 600: 582: 579: 578: 558: 553: 547: 544: 543: 512: 509: 508: 488: 483: 471: 468: 467: 446: 441: 435: 432: 431: 414: 410: 408: 405: 404: 381: 377: 369: 366: 365: 349: 346: 345: 341: 325: 322: 321: 317: 297: 293: 285: 282: 281: 265: 262: 261: 244: 240: 238: 235: 234: 227: 223: 219: 212: 196: 189: 182: 162: 144: 117:random variable 99: 40:nonconstructive 28: 23: 22: 15: 12: 11: 5: 3120: 3110: 3109: 3104: 3099: 3084: 3081: 3080: 3079: 3069: 3058: 3052: 3047:, J. Vondrak. 3042: 2991: 2948: 2931: 2928: 2927: 2926: 2918: 2915: 2914: 2913: 2908: 2903: 2898: 2893: 2888: 2882: 2881: 2865: 2862: 2830: 2825: 2821: 2818: 2812: 2787: 2783: 2779: 2776: 2772: 2769: 2749:vertices from 2729: 2728: 2708: 2703: 2697: 2694: 2690: 2685: 2681: 2678: 2664: 2663: 2652: 2649: 2646: 2643: 2640: 2637: 2632: 2629: 2626: 2623: 2620: 2617: 2614: 2611: 2608: 2605: 2602: 2599: 2594: 2591: 2586: 2582: 2578: 2571: 2567: 2564: 2561: 2558: 2555: 2552: 2549: 2543: 2539: 2533: 2529: 2525: 2519: 2515: 2512: 2509: 2506: 2503: 2500: 2494: 2490: 2487: 2484: 2481: 2475: 2470: 2467: 2462: 2456: 2453: 2450: 2447: 2444: 2441: 2438: 2413: 2412: 2400: 2393: 2390: 2386: 2380: 2358: 2357: 2346: 2335: 2332: 2329: 2326: 2323: 2320: 2313: 2310: 2305: 2301: 2297: 2294: 2288: 2284: 2281: 2278: 2272: 2266: 2263: 2258: 2252: 2249: 2244: 2238: 2235: 2232: 2227: 2224: 2221: 2217: 2211: 2208: 2203: 2198: 2194: 2188: 2184: 2178: 2175: 2172: 2167: 2164: 2161: 2157: 2151: 2148: 2143: 2140: 2137: 2134: 2131: 2126: 2123: 2118: 2114: 2107: 2104: 2098: 2095: 2091: 2087: 2059: 2058: 2045: 2040: 2036: 2030: 2024: 2021: 2018: 2015: 2012: 2009: 2006: 2003: 2000: 1997: 1992: 1989: 1953: 1952: 1850: 1849:Second example 1847: 1844: 1843: 1841: 1840: 1828: 1825: 1817: 1812: 1809: 1804: 1798: 1795: 1791: 1784: 1779: 1776: 1771: 1765: 1758: 1753: 1750: 1745: 1739: 1735: 1727: 1722: 1719: 1714: 1708: 1702: 1697: 1694: 1689: 1682: 1675: 1670: 1667: 1662: 1656: 1645: 1628: 1623: 1620: 1615: 1609: 1603: 1598: 1595: 1590: 1583: 1576: 1571: 1568: 1563: 1557: 1546: 1543: 1527: 1522: 1519: 1514: 1508: 1484: 1479: 1476: 1471: 1453: 1438: 1433: 1430: 1425: 1413:-subgraphs is 1398: 1397: 1306: 1305: 1294: 1291: 1283: 1278: 1275: 1270: 1264: 1261: 1257: 1250: 1245: 1242: 1237: 1231: 1228: 1225: 1220: 1216: 1212: 1209: 1206: 1203: 1149: 1148: 1137: 1129: 1124: 1121: 1116: 1110: 1107: 1103: 1096: 1091: 1088: 1083: 1077: 1074: 1071: 1066: 1062: 1058: 1055: 1052: 1049: 1026: 1007: 1006: 995: 987: 982: 979: 974: 968: 965: 961: 954: 949: 946: 941: 935: 932: 929: 924: 919: 915: 911: 908: 905: 902: 897: 894: 891: 888: 885: 882: 877: 874: 871: 867: 841: 836: 832: 811: 808: 803: 798: 794: 790: 787: 784: 781: 761: 758: 755: 752: 749: 746: 722: 702: 699: 696: 693: 690: 687: 669: 668: 652: 647: 644: 639: 633: 629: 625: 622: 619: 616: 613: 608: 603: 599: 595: 592: 589: 586: 561: 556: 552: 531: 528: 525: 522: 519: 516: 496: 491: 486: 482: 478: 475: 464:expected value 449: 444: 440: 417: 413: 389: 384: 380: 376: 373: 353: 329: 305: 300: 296: 292: 289: 269: 247: 243: 186:complete graph 181: 178: 143: 140: 132:Chernoff bound 113:expected value 98: 95: 75:linear algebra 26: 9: 6: 4: 3: 2: 3119: 3108: 3105: 3103: 3100: 3098: 3097:Combinatorics 3095: 3094: 3092: 3078: 3077:0 444 81624 0 3074: 3070: 3067: 3063: 3059: 3057: 3053: 3050: 3046: 3043: 3039: 3035: 3031: 3027: 3023: 3019: 3014: 3009: 3005: 3001: 2997: 2992: 2988: 2984: 2980: 2976: 2971: 2966: 2962: 2958: 2954: 2949: 2946: 2945:0-471-37046-0 2942: 2938: 2934: 2933: 2924: 2921: 2920: 2912: 2909: 2907: 2904: 2902: 2899: 2897: 2894: 2892: 2889: 2887: 2884: 2883: 2879: 2873: 2868: 2861: 2857: 2846: 2828: 2823: 2819: 2816: 2810: 2785: 2781: 2777: 2774: 2770: 2767: 2757: 2746: 2736: 2706: 2701: 2695: 2692: 2688: 2683: 2679: 2676: 2669: 2668: 2667: 2650: 2644: 2638: 2635: 2627: 2624: 2621: 2618: 2615: 2612: 2609: 2606: 2603: 2597: 2592: 2589: 2584: 2580: 2576: 2569: 2562: 2559: 2556: 2550: 2547: 2541: 2537: 2531: 2527: 2523: 2517: 2510: 2507: 2504: 2498: 2488: 2485: 2482: 2468: 2465: 2454: 2448: 2445: 2442: 2429: 2428: 2427: 2417: 2391: 2388: 2384: 2370: 2363: 2360: 2359: 2347: 2333: 2327: 2321: 2318: 2311: 2308: 2303: 2299: 2295: 2292: 2286: 2282: 2279: 2276: 2270: 2264: 2261: 2256: 2250: 2247: 2242: 2236: 2233: 2230: 2225: 2222: 2219: 2215: 2209: 2206: 2201: 2196: 2192: 2186: 2182: 2176: 2173: 2170: 2165: 2162: 2159: 2155: 2149: 2146: 2141: 2135: 2129: 2124: 2121: 2116: 2112: 2105: 2102: 2096: 2093: 2089: 2078: 2077: 2076: 2074: 2069: 2043: 2038: 2034: 2028: 2022: 2016: 2013: 2010: 2004: 2001: 1998: 1995: 1990: 1987: 1977: 1976: 1975: 1957: 1944: 1936: 1933: 1932: 1931: 1924: 1920: 1890: 1880: 1872: 1856: 1826: 1823: 1810: 1807: 1796: 1793: 1789: 1777: 1774: 1751: 1748: 1737: 1733: 1720: 1717: 1706: 1695: 1692: 1680: 1668: 1665: 1654: 1646: 1621: 1618: 1607: 1596: 1593: 1581: 1569: 1566: 1555: 1547: 1544: 1520: 1517: 1506: 1477: 1474: 1458: 1454: 1431: 1428: 1412: 1408: 1407: 1403: 1399: 1395: 1393: 1381: 1376: 1370: 1369:exponentially 1364: 1360: 1356: 1345: 1341: 1337: 1332: 1331:Ramsey number 1327: 1319: 1312: 1292: 1289: 1276: 1273: 1262: 1259: 1255: 1243: 1240: 1229: 1218: 1214: 1207: 1201: 1194: 1193: 1192: 1178: 1135: 1122: 1119: 1108: 1105: 1101: 1089: 1086: 1075: 1064: 1060: 1053: 1047: 1040: 1039: 1038: 1024: 1016: 1012: 993: 980: 977: 966: 963: 959: 947: 944: 933: 922: 917: 913: 906: 900: 892: 889: 886: 880: 875: 872: 869: 865: 857: 856: 855: 839: 834: 830: 801: 796: 792: 785: 779: 756: 753: 750: 744: 720: 697: 694: 691: 685: 676: 645: 642: 631: 627: 623: 620: 617: 606: 601: 597: 590: 584: 577: 576: 575: 559: 554: 550: 526: 523: 520: 514: 489: 484: 480: 473: 465: 447: 442: 438: 415: 411: 403: 382: 378: 371: 351: 327: 298: 294: 287: 267: 245: 241: 231: 216: 210: 206: 202: 194: 187: 180:First example 177: 173: 169: 165: 161: 160:Ramsey number 157: 153: 149: 139: 137: 133: 129: 124: 120: 118: 114: 109: 107: 102: 94: 92: 88: 84: 80: 79:real analysis 76: 72: 71:number theory 68: 63: 61: 57: 53: 49: 45: 44:combinatorics 41: 37: 33: 19: 3003: 3000:Can. J. Math 2999: 2960: 2957:Can. J. Math 2956: 2936: 2911:Random graph 2858: 2844: 2755: 2744: 2737: 2730: 2665: 2415: 2414: 2367:contains no 2361: 2067: 2060: 1974:vertices is 1955: 1954: 1942: 1934: 1922: 1918: 1891: 1885:is at least 1855:graph theory 1852: 1456: 1410: 1402: 1377: 1362: 1358: 1354: 1343: 1339: 1335: 1328: 1326:-subgraphs. 1317: 1310: 1307: 1150: 1010: 1008: 733:ranges from 677: 670: 233:For any set 232: 217: 183: 171: 167: 163: 145: 125: 121: 110: 105: 103: 100: 97:Introduction 64: 59: 35: 29: 3045:J. Matoušek 3006:: 346–352. 2362:Property 2. 2071:. Hence by 1935:Property 1. 1015:independent 152:tournaments 67:mathematics 56:probability 32:mathematics 3091:Categories 2930:References 1647:Hence, if 1011:regardless 134:, and the 48:Paul Erdős 3083:Footnotes 3008:CiteSeerX 2987:122784453 2963:: 34–38. 2775:≥ 2625:− 2619:⁡ 2610:− 2598:⋅ 2585:− 2560:− 2542:− 2524:≤ 2508:− 2486:− 2455:≤ 2446:≥ 2399:⌉ 2379:⌈ 2304:− 2280:− 2257:≤ 2234:− 2216:∑ 2174:− 2156:∑ 2142:≤ 2117:≤ 2029:≤ 2014:− 2005:⋅ 1999:⋅ 1797:− 1764:⇔ 1707:− 1608:− 1263:− 1109:− 967:− 866:∑ 822:over all 632:− 624:⋅ 542:edges in 3038:15134755 2864:See also 2829:⌉ 2820:′ 2811:⌈ 2771:′ 2702:⌉ 2684:⌈ 2371:of size 2075:we have 209:subgraph 193:vertices 148:theorems 115:of some 69:such as 3030:0120168 2979:0102081 1177:integer 402:subsets 203:of the 89:), and 60:certain 52:proving 3075:  3068:, 2017 3064:  3036:  3028:  3010:  2985:  2977:  2943:  2416:Proof. 1956:Proof. 1871:cycles 462:, the 316:to be 130:, the 85:(e.g. 77:, and 50:, for 34:, the 3034:S2CID 2983:S2CID 2666:when 1455:Each 1384:(1.1) 1371:with 205:graph 201:edges 38:is a 3073:ISBN 3062:ISBN 2941:ISBN 2418:Let 2097:> 1958:Let 1896:and 1861:and 1824:< 1734:< 1392:open 1315:and 1290:< 3018:doi 2965:doi 2759:on 2725:1/2 2354:1/2 1908:on 1881:of 1320:= 4 1313:= 5 854:is 737:to 466:of 260:of 224:1/2 220:1/2 211:on 188:on 106:not 30:In 3093:: 3032:. 3026:MR 3024:. 3016:. 3004:13 3002:. 2998:. 2981:. 2975:MR 2973:. 2961:11 2959:. 2955:. 2856:. 2845:G′ 2842:. 2756:G′ 2747:/2 2616:ln 2437:Pr 2086:Pr 1945:/2 1921:= 1889:? 1375:. 1361:, 1342:, 176:. 170:, 138:. 93:. 73:, 3040:. 3020:: 2989:. 2967:: 2947:. 2854:k 2850:k 2824:k 2817:n 2800:g 2786:2 2782:/ 2778:n 2768:n 2751:G 2745:n 2740:G 2733:n 2727:. 2721:n 2707:. 2696:k 2693:2 2689:n 2680:= 2677:y 2651:, 2648:) 2645:1 2642:( 2639:o 2636:= 2631:) 2628:p 2622:n 2613:2 2607:y 2604:p 2601:( 2593:2 2590:y 2581:e 2577:= 2570:2 2566:) 2563:1 2557:y 2554:( 2551:y 2548:p 2538:e 2532:y 2528:n 2518:2 2514:) 2511:1 2505:y 2502:( 2499:y 2493:) 2489:p 2483:1 2480:( 2474:) 2469:y 2466:n 2461:( 2452:) 2449:y 2443:Y 2440:( 2424:G 2420:Y 2411:. 2392:k 2389:2 2385:n 2365:G 2356:. 2350:n 2334:. 2331:) 2328:1 2325:( 2322:o 2319:= 2312:g 2309:1 2300:n 2296:g 2293:= 2287:g 2283:1 2277:g 2271:n 2265:n 2262:g 2251:g 2248:i 2243:n 2237:1 2231:g 2226:3 2223:= 2220:i 2210:n 2207:1 2202:= 2197:i 2193:n 2187:i 2183:p 2177:1 2171:g 2166:3 2163:= 2160:i 2150:n 2147:1 2139:] 2136:X 2133:[ 2130:E 2125:n 2122:2 2113:) 2106:2 2103:n 2094:X 2090:( 2068:p 2063:G 2044:2 2039:i 2035:n 2023:! 2020:) 2017:i 2011:n 2008:( 2002:i 1996:2 1991:! 1988:n 1972:n 1968:i 1964:g 1960:X 1951:. 1949:g 1943:n 1938:G 1928:G 1923:n 1919:p 1914:G 1910:n 1906:G 1902:n 1898:k 1894:g 1887:k 1883:G 1875:g 1867:G 1863:k 1859:g 1827:1 1816:) 1811:2 1808:r 1803:( 1794:1 1790:2 1783:) 1778:r 1775:n 1770:( 1757:) 1752:2 1749:n 1744:( 1738:2 1726:) 1721:2 1718:r 1713:( 1701:) 1696:2 1693:n 1688:( 1681:2 1674:) 1669:r 1666:n 1661:( 1655:2 1644:. 1627:) 1622:2 1619:r 1614:( 1602:) 1597:2 1594:n 1589:( 1582:2 1575:) 1570:r 1567:n 1562:( 1556:2 1526:) 1521:2 1518:r 1513:( 1507:2 1483:) 1478:2 1475:r 1470:( 1457:r 1452:. 1437:) 1432:r 1429:n 1424:( 1411:r 1388:r 1373:r 1365:) 1363:r 1359:r 1357:( 1355:R 1350:n 1346:) 1344:r 1340:r 1338:( 1336:R 1324:r 1318:r 1311:n 1293:1 1282:) 1277:2 1274:r 1269:( 1260:1 1256:2 1249:) 1244:r 1241:n 1236:( 1230:= 1227:] 1224:) 1219:r 1215:S 1211:( 1208:X 1205:[ 1202:E 1189:1 1185:0 1183:( 1181:0 1173:r 1169:1 1165:r 1161:1 1157:r 1153:1 1136:. 1128:) 1123:2 1120:r 1115:( 1106:1 1102:2 1095:) 1090:r 1087:n 1082:( 1076:= 1073:] 1070:) 1065:r 1061:S 1057:( 1054:X 1051:[ 1048:E 1025:r 994:. 986:) 981:2 978:r 973:( 964:1 960:2 953:) 948:r 945:n 940:( 934:= 931:] 928:) 923:i 918:r 914:S 910:( 907:X 904:[ 901:E 896:) 893:r 890:, 887:n 884:( 881:C 876:1 873:= 870:i 840:i 835:r 831:S 810:] 807:) 802:i 797:r 793:S 789:( 786:X 783:[ 780:E 760:) 757:r 754:, 751:n 748:( 745:C 735:1 721:i 701:) 698:r 695:, 692:n 689:( 686:C 673:2 651:) 646:2 643:r 638:( 628:2 621:2 618:= 615:] 612:) 607:i 602:r 598:S 594:( 591:X 588:[ 585:E 560:i 555:r 551:S 530:) 527:2 524:, 521:r 518:( 515:C 495:) 490:i 485:r 481:S 477:( 474:X 448:i 443:r 439:S 416:r 412:S 388:) 383:r 379:S 375:( 372:X 352:r 342:0 328:r 318:1 304:) 299:r 295:S 291:( 288:X 268:r 246:r 242:S 228:r 213:r 197:n 190:n 174:) 172:r 168:r 166:( 164:R 20:)

Index

Probabilistic combinatorics
mathematics
nonconstructive
combinatorics
Paul Erdős
proving
probability
mathematics
number theory
linear algebra
real analysis
computer science
randomized rounding
information theory
expected value
random variable
Markov's inequality
Chernoff bound
Lovász local lemma
theorems
tournaments
Hamiltonian cycles
Ramsey number
complete graph
vertices
edges
graph
subgraph
subsets
expected value

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