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Lehmer code

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2252: 1064: 1091:} is sought). Alternatively the entries of the Lehmer code can be processed from left to right, and interpreted as a number determining the next choice of an element as indicated above; this requires maintaining a list of available elements, from which each chosen element is removed. In the example this would mean choosing element 1 from {A,B,C,D,E,F,G} (which is B) then element 4 from {A,C,D,E,F,G} (which is F), then element 0 from {A,C,D,E,G} (giving A) and so on, reconstructing the sequence B,F,A,G,D,E,C. 775: 1059:{\displaystyle {\begin{matrix}\mathbf {1} &5&0&6&3&4&2\\1&\mathbf {4} &0&5&2&3&1\\1&4&\mathbf {0} &4&2&3&1\\1&4&0&\mathbf {3} &1&2&0\\1&4&0&3&\mathbf {1} &2&0\\1&4&0&3&1&\mathbf {1} &0\\1&4&0&3&1&1&\mathbf {0} \\\end{matrix}}} 2228:
to a friend of his at a time when he was trying to make up his mind and choose one out eleven prospective brides as his second wife. His first marriage had been an unhappy one, having been arranged without himself being consulted, and he was thus very concerned that he could reach the right decision.
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This number to encode each object can be found by direct counting, in several ways (directly counting inversions, or correcting the total number of objects smaller than a given one, which is its sequence number starting from 0 in the set, by those that are unavailable at its position). Another method
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different ways (because there are now 2 forbidden values), and so forth. Translating this freedom of choice at each step into a number, one obtains an encoding algorithm, one that finds the Lehmer code of a given permutation. One need not suppose the objects permuted to be numbers, but one needs a
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The interviewer thus knows the rank of the k applicant, therefore, at the moment of making his k decision, the interviewer knows only the k first elements of the Lehmer code whereas he would need to know all of them to make a well informed decision. To determine the optimal strategies (i.e. the
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This is an optimal stop problem, a classic in decision theory, statistics and applied probabilities, where a random permutation is gradually revealed through the first elements of its Lehmer code, and where the goal is to stop exactly at the element k such as σ(k)=n, whereas the only available
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In less mathematical words : a series of n applicants are interviewed one after the other. The interviewer must hire the best applicant, but must make his decision (“Hire” or “Not hire”) on the spot, without interviewing the next applicant (and
635:, or by counting non-inversions rather than inversions; while this does not produce a fundamentally different type of encoding, some properties of the encoding will change correspondingly. In particular counting inversions with a fixed smaller value 2178: 1396: 191: 768:
is no longer available). Concretely a Lehmer code for the permutation B,F,A,G,D,E,C of letters, ordered alphabetically, would first give the list of sequence numbers 1,5,0,6,3,4,2, which is successively transformed
1571: 129: 1188: 1385: 2059: 1795: 530:, which is also the number of adjacent transpositions that are needed to transform the permutation into the identity permutation. Other properties of the Lehmer code include that the 1789: 1242: 1991: 166:
numbers, but not all such sequences are valid since every number must be used only once. By contrast the encodings considered here choose the first number from a set of
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where the final line is the Lehmer code (at each line one subtracts 1 from the larger entries to the right of the boldface element to form the next line).
2075: 1533:{\displaystyle \{\omega \in B(k)\}\Leftrightarrow \{L(k,\omega )=0\}\quad {\text{and}}\quad \{\omega \in H(k)\}\Leftrightarrow \{L(k,\omega )=k-1\}.} 342:{\displaystyle L(\sigma )=(L(\sigma )_{1},\ldots ,L(\sigma )_{n})\quad {\text{where}}\quad L(\sigma )_{i}=\#\{j>i:\sigma _{j}<\sigma _{i}\},} 1730:{\displaystyle N_{b}(\omega )=\sum _{1\leq k\leq n}\ 1\!\!1_{B(k)}\quad {\text{and}}\quad N_{b}(\omega )=\sum _{1\leq k\leq n}\ 1\!\!1_{H(k)}.} 2242: 2364: 69: 177:
values, and so forth decreasing the number of possibilities until the last number for which only a single fixed value is allowed;
1076:, in order from right to left, correct the items to its right by adding 1 to all those (currently) greater than or equal to 1119: 1354: 2187: 1276: 760:, in order from left to right, correct the items to its right by subtracting 1 from all entries (still) greater than 2408: 1072:
For decoding a Lehmer code into a permutation of a given set, the latter procedure may be reversed: for each entry
45: 1998: 1939:{\displaystyle \mathbb {P} (B(k))=\mathbb {P} (L(k)=0)=\mathbb {P} (H(k))=\mathbb {P} (L(k)=k-1)={\tfrac {1}{k}}.} 1245: 691:
of the set of objects. Since the code numbers are to start from 0, the appropriate number to encode each object
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strategy maximizing the probability of a win), the statistical properties of the Lehmer code are crucial.
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by is the number of objects that were available at that point (so they do not occur before position
1955: 756:} obtained by representing each object by its mentioned sequence number, and then for each entry 749:
which is in-place, but not really more efficient, is to start with the permutation of {0, 1, ...
591: 41: 2398: 550:), that any value 0 in the code represents a right-to-left minimum in the permutation (i.e., a 2372: 2186:
notation), which allows us to recover the product formula for the generating function of the
1087:} as sequence numbers (which amounts to adding 1 to each entry if a permutation of {1, 2, ... 2403: 531: 185:
can be defined, the Lehmer code has several additional useful properties; it is the sequence
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different ways (because choosing the same number as the first is forbidden), the next in
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information (the k first values of the Lehmer code) is not sufficient to compute σ(k).
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sequence of numbers chosen from these sets encodes a single permutation. While several
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Two similar vectors are in use. One of them is often called inversion vector, e.g. by
2298: 2251: 2225: 2199: 1280: 2332: 2221: 2173:{\displaystyle G(s)=\prod _{k=1}^{n}G_{k}(s)\ =\ {\frac {s^{\overline {n}}}{n!}}} 1272: 1105: 688: 2392: 2238: 534:
of the encodings of two permutations is the same as that of their sequences (
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similarly signifies a right-to-left maximum, and that the Lehmer code of
33: 17: 2346: 1343:) be the event "there is right-to-left minimum (resp. maximum) at rank 713:
actually chosen. (Inevitably such objects must appear at some position
650:, which can be seen to be the Lehmer code of the inverse permutation. 2278:
Lehmer, D.H. (1960), "Teaching combinatorial tricks to a computer",
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Variations of this encoding can be obtained by counting inversions (
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in lexicographical order (numbering the positions starting from 0).
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Proc. Sympos. Appl. Math. Combinatorial Analysis, Amer. Math. Soc.
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Inversion (discrete mathematics) § Inversion related vectors
2365:"A permutation representation that knows what "Eulerian" means" 1558:) of right-to-left minimum (resp. maximum) for the permutation 731:) will be an inversion, which shows that this number is indeed 1387:
which exhibit a right-to-left minimum (resp. maximum) at rank
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is strictly smaller (resp. strictly bigger) than each element
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representation of its position in the list of permutations of
124:{\displaystyle n!=n\times (n-1)\times \cdots \times 2\times 1} 2299:"Sur la numération factorielle, application aux permutations" 666:
objects is to observe that the first object can be chosen in
1286: 1080:; finally interpret the resulting permutation of {0, 1, ... 1279:, because they are projections on different factors of a 2384:, vol. 3, Reading: Addison-Wesley, pp. 12–13 1922: 1750: 1358: 780: 764:(to reflect the fact that the object corresponding to 2369:
Discrete Mathematics and Theoretical Computer Science
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The Lehmer code makes use of the fact that there are
2362: 2247: 2323:(1989), "Who solved the secretary problem ?", 1183:{\displaystyle \times \times \cdots \times \times } 55:, but the code had been known since 1888 at least. 2172: 2053: 1985: 1938: 1783: 1729: 1532: 1380:{\displaystyle \scriptstyle \ {\mathfrak {S}}_{n}} 1379: 1236: 1182: 1058: 341: 123: 1963: 1962: 1773: 1757: 1704: 1703: 1626: 1625: 1099: 391:that are smaller than it, a number between 0 and 2390: 2363:Mantaci, Roberto; Rakotondrajao, Fanja (2001), 1566:each with a respective parameter of 1/k : 1095:Applications to combinatorics and probabilities 617:, by counting inversions with a fixed smaller 2303:Bulletin de la Société Mathématique de France 1275:on , and these random variables are mutually 1104:The Lehmer code defines a bijection from the 2054:{\displaystyle G_{k}(s)={\frac {k-1+s}{k}},} 1524: 1491: 1485: 1464: 1454: 1427: 1421: 1400: 1231: 1201: 333: 295: 170:values, the next number from a fixed set of 40:numbers. It is an instance of a scheme for 2336: 1884: 1858: 1826: 1800: 1287:Number of right-to-left minima and maxima 704:), but which are smaller than the object 51:The Lehmer code is named in reference to 2319: 2193: 653: 2313: 2296: 1562:can be written as a sum of independent 2391: 2290: 2277: 2213:without interviewing all applicants). 2063:therefore the generating function of 658:The usual way to prove that there are 162:, then it is encoded by a sequence of 2379: 2271: 526:is the total number of inversions of 2232: 1784:{\displaystyle \scriptstyle \ \!],} 1365: 1237:{\displaystyle \{0,1,\ldots ,k-1\}} 672:different ways, the next object in 13: 2188:Stirling numbers of the first kind 1952:for the Bernoulli random variable 292: 14: 2420: 470:counts the number of inversions ( 2250: 1291:Definition : In a sequence 1271:defines a uniformly distributed 1048: 1004: 960: 916: 872: 828: 784: 2382:The art of computer programming 2356: 1652: 1646: 1463: 1457: 1351:is the set of the permutations 366:counts the number of terms in ( 269: 263: 2297:Laisant, Charles-Ange (1888), 2131: 2125: 2088: 2082: 2018: 2012: 1978: 1972: 1915: 1900: 1894: 1888: 1877: 1874: 1868: 1862: 1851: 1842: 1836: 1830: 1819: 1816: 1810: 1804: 1774: 1770: 1758: 1754: 1719: 1713: 1669: 1663: 1641: 1635: 1591: 1585: 1509: 1497: 1488: 1482: 1476: 1445: 1433: 1424: 1418: 1412: 1244:. As a consequence, under the 1177: 1171: 1165: 1159: 1147: 1135: 1129: 1123: 1100:Independence of relative ranks 280: 273: 260: 251: 244: 223: 216: 210: 204: 198: 142:is specified by the sequence ( 134:permutations of a sequence of 100: 88: 1: 2264: 1986:{\displaystyle 1\!\!1_{B(k)}} 646:gives the inversion table of 2371:(4): 101–108, archived from 2154: 1743:follows the uniform law on 662:! different permutations of 7: 572:to its right), and a value 158:) of its images of 1, ..., 58: 10: 2425: 2197: 1564:Bernoulli random variables 631:rather than smaller index 452:is called an inversion of 138:numbers. If a permutation 1116:to the Cartesian product 1190:, where designates the 352:in other words the term 44:and is an example of an 2409:Resampling (statistics) 592:factorial number system 28:is a particular way to 2174: 2114: 2055: 1987: 1940: 1785: 1731: 1534: 1381: 1332:, i.e., to its right. 1238: 1184: 1060: 343: 125: 42:numbering permutations 2338:10.1214/ss/1177012493 2224:clearly exposed this 2194:The secretary problem 2175: 2094: 2056: 1988: 1941: 1786: 1732: 1535: 1382: 1304:right-to-left minimum 1239: 1185: 1061: 654:Encoding and decoding 532:lexicographical order 344: 126: 20:and in particular in 2076: 1999: 1956: 1796: 1747: 1572: 1397: 1355: 1246:uniform distribution 1198: 1120: 776: 192: 70: 53:Derrick Henry Lehmer 2380:Knuth, Don (1981), 2325:Statistical Science 2321:Ferguson, Thomas S. 1950:generating function 590:coincides with the 414:A pair of indices ( 2258:Mathematics portal 2170: 2051: 1983: 1936: 1931: 1781: 1780: 1727: 1696: 1618: 1530: 1391:. We clearly have 1377: 1376: 1234: 1180: 1056: 1054: 613:rather than fixed 486:. It follows that 482:fixed and varying 411:different values. 382:) to the right of 339: 121: 2226:secretary problem 2200:Secretary problem 2168: 2157: 2142: 2136: 2046: 1930: 1753: 1699: 1675: 1650: 1621: 1597: 1461: 1361: 1281:Cartesian product 561:smaller than any 267: 36:of a sequence of 2416: 2385: 2376: 2350: 2349: 2340: 2317: 2311: 2310: 2294: 2288: 2287: 2275: 2260: 2255: 2254: 2233:Similar concepts 2184:rising factorial 2179: 2177: 2176: 2171: 2169: 2167: 2159: 2158: 2150: 2144: 2140: 2134: 2124: 2123: 2113: 2108: 2060: 2058: 2057: 2052: 2047: 2042: 2025: 2011: 2010: 1992: 1990: 1989: 1984: 1982: 1981: 1945: 1943: 1942: 1937: 1932: 1923: 1887: 1861: 1829: 1803: 1790: 1788: 1787: 1782: 1751: 1736: 1734: 1733: 1728: 1723: 1722: 1697: 1695: 1662: 1661: 1651: 1648: 1645: 1644: 1619: 1617: 1584: 1583: 1542:Thus the number 1539: 1537: 1536: 1531: 1462: 1459: 1386: 1384: 1383: 1378: 1375: 1374: 1369: 1368: 1359: 1257:, the component 1243: 1241: 1240: 1235: 1189: 1187: 1186: 1181: 1086: 1065: 1063: 1062: 1057: 1055: 1051: 1007: 963: 919: 875: 831: 787: 755: 722: 685: 678: 671: 645: 630: 581: 571: 560: 525: 451: 431: 410: 400: 348: 346: 345: 340: 332: 331: 319: 318: 288: 287: 268: 265: 259: 258: 231: 230: 176: 130: 128: 127: 122: 2424: 2423: 2419: 2418: 2417: 2415: 2414: 2413: 2389: 2388: 2359: 2354: 2353: 2318: 2314: 2295: 2291: 2276: 2272: 2267: 2256: 2249: 2235: 2222:Johannes Kepler 2202: 2196: 2180: 2160: 2149: 2145: 2143: 2119: 2115: 2109: 2098: 2077: 2074: 2073: 2068: 2061: 2026: 2024: 2006: 2002: 2000: 1997: 1996: 1968: 1964: 1957: 1954: 1953: 1946: 1921: 1883: 1857: 1825: 1799: 1797: 1794: 1793: 1748: 1745: 1744: 1737: 1709: 1705: 1679: 1657: 1653: 1647: 1631: 1627: 1601: 1579: 1575: 1573: 1570: 1569: 1555: 1547: 1540: 1458: 1398: 1395: 1394: 1370: 1364: 1363: 1362: 1356: 1353: 1352: 1326: 1319: 1300: 1296: 1289: 1273:random variable 1270: 1256: 1199: 1196: 1195: 1121: 1118: 1117: 1115: 1106:symmetric group 1102: 1097: 1081: 1053: 1052: 1047: 1045: 1040: 1035: 1030: 1025: 1020: 1014: 1013: 1008: 1003: 1001: 996: 991: 986: 981: 975: 974: 969: 964: 959: 957: 952: 947: 942: 936: 935: 930: 925: 920: 915: 913: 908: 903: 897: 896: 891: 886: 881: 876: 871: 869: 864: 858: 857: 852: 847: 842: 837: 832: 827: 825: 819: 818: 813: 808: 803: 798: 793: 788: 783: 779: 777: 774: 773: 750: 744: 714: 712: 699: 680: 673: 667: 656: 644: 636: 629: 621: 573: 570: 562: 559: 551: 549: 540: 524: 510: 498: 487: 469: 450: 441: 433: 423: 402: 401:, allowing for 392: 390: 381: 372: 365: 327: 323: 314: 310: 283: 279: 264: 254: 250: 226: 222: 193: 190: 189: 171: 157: 148: 71: 68: 67: 61: 12: 11: 5: 2422: 2412: 2411: 2406: 2401: 2387: 2386: 2377: 2358: 2355: 2352: 2351: 2331:(3): 282–289, 2312: 2289: 2269: 2268: 2266: 2263: 2262: 2261: 2234: 2231: 2198:Main article: 2195: 2192: 2166: 2163: 2156: 2153: 2148: 2139: 2133: 2130: 2127: 2122: 2118: 2112: 2107: 2104: 2101: 2097: 2093: 2090: 2087: 2084: 2081: 2072: 2066: 2050: 2045: 2041: 2038: 2035: 2032: 2029: 2023: 2020: 2017: 2014: 2009: 2005: 1995: 1980: 1977: 1974: 1971: 1967: 1961: 1935: 1929: 1926: 1920: 1917: 1914: 1911: 1908: 1905: 1902: 1899: 1896: 1893: 1890: 1886: 1882: 1879: 1876: 1873: 1870: 1867: 1864: 1860: 1856: 1853: 1850: 1847: 1844: 1841: 1838: 1835: 1832: 1828: 1824: 1821: 1818: 1815: 1812: 1809: 1806: 1802: 1792: 1779: 1776: 1772: 1769: 1766: 1763: 1760: 1756: 1726: 1721: 1718: 1715: 1712: 1708: 1702: 1694: 1691: 1688: 1685: 1682: 1678: 1674: 1671: 1668: 1665: 1660: 1656: 1643: 1640: 1637: 1634: 1630: 1624: 1616: 1613: 1610: 1607: 1604: 1600: 1596: 1593: 1590: 1587: 1582: 1578: 1568: 1553: 1545: 1529: 1526: 1523: 1520: 1517: 1514: 1511: 1508: 1505: 1502: 1499: 1496: 1493: 1490: 1487: 1484: 1481: 1478: 1475: 1472: 1469: 1466: 1456: 1453: 1450: 1447: 1444: 1441: 1438: 1435: 1432: 1429: 1426: 1423: 1420: 1417: 1414: 1411: 1408: 1405: 1402: 1393: 1373: 1367: 1324: 1317: 1298: 1294: 1288: 1285: 1266: 1252: 1233: 1230: 1227: 1224: 1221: 1218: 1215: 1212: 1209: 1206: 1203: 1179: 1176: 1173: 1170: 1167: 1164: 1161: 1158: 1155: 1152: 1149: 1146: 1143: 1140: 1137: 1134: 1131: 1128: 1125: 1111: 1101: 1098: 1096: 1093: 1067: 1066: 1050: 1046: 1044: 1041: 1039: 1036: 1034: 1031: 1029: 1026: 1024: 1021: 1019: 1016: 1015: 1012: 1009: 1006: 1002: 1000: 997: 995: 992: 990: 987: 985: 982: 980: 977: 976: 973: 970: 968: 965: 962: 958: 956: 953: 951: 948: 946: 943: 941: 938: 937: 934: 931: 929: 926: 924: 921: 918: 914: 912: 909: 907: 904: 902: 899: 898: 895: 892: 890: 887: 885: 882: 880: 877: 874: 870: 868: 865: 863: 860: 859: 856: 853: 851: 848: 846: 843: 841: 838: 836: 833: 830: 826: 824: 821: 820: 817: 814: 812: 809: 807: 804: 802: 799: 797: 794: 792: 789: 786: 782: 781: 740: 708: 695: 689:total ordering 655: 652: 640: 625: 566: 555: 545: 538: 520: 508: 496: 465: 446: 437: 386: 377: 370: 361: 350: 349: 338: 335: 330: 326: 322: 317: 313: 309: 306: 303: 300: 297: 294: 291: 286: 282: 278: 275: 272: 262: 257: 253: 249: 246: 243: 240: 237: 234: 229: 225: 221: 218: 215: 212: 209: 206: 203: 200: 197: 153: 146: 132: 131: 120: 117: 114: 111: 108: 105: 102: 99: 96: 93: 90: 87: 84: 81: 78: 75: 60: 57: 32:each possible 9: 6: 4: 3: 2: 2421: 2410: 2407: 2405: 2402: 2400: 2399:Combinatorics 2397: 2396: 2394: 2383: 2378: 2375:on 2004-11-16 2374: 2370: 2366: 2361: 2360: 2348: 2344: 2339: 2334: 2330: 2326: 2322: 2316: 2308: 2305:(in French), 2304: 2300: 2293: 2285: 2281: 2274: 2270: 2259: 2253: 2248: 2246: 2244: 2240: 2239:Wolfram Alpha 2230: 2227: 2223: 2218: 2214: 2212: 2206: 2201: 2191: 2189: 2185: 2164: 2161: 2151: 2146: 2137: 2128: 2120: 2116: 2110: 2105: 2102: 2099: 2095: 2091: 2085: 2079: 2071: 2069: 2048: 2043: 2039: 2036: 2033: 2030: 2027: 2021: 2015: 2007: 2003: 1994: 1975: 1969: 1965: 1959: 1951: 1933: 1927: 1924: 1918: 1912: 1909: 1906: 1903: 1897: 1891: 1880: 1871: 1865: 1854: 1848: 1845: 1839: 1833: 1822: 1813: 1807: 1791: 1777: 1767: 1764: 1761: 1742: 1724: 1716: 1710: 1706: 1700: 1692: 1689: 1686: 1683: 1680: 1676: 1672: 1666: 1658: 1654: 1638: 1632: 1628: 1622: 1614: 1611: 1608: 1605: 1602: 1598: 1594: 1588: 1580: 1576: 1567: 1565: 1561: 1557: 1549: 1527: 1521: 1518: 1515: 1512: 1506: 1503: 1500: 1494: 1479: 1473: 1470: 1467: 1451: 1448: 1442: 1439: 1436: 1430: 1415: 1409: 1406: 1403: 1392: 1390: 1371: 1350: 1346: 1342: 1338: 1333: 1331: 1327: 1320: 1313: 1309: 1305: 1301: 1284: 1282: 1278: 1274: 1269: 1264: 1260: 1255: 1251: 1247: 1228: 1225: 1222: 1219: 1216: 1213: 1210: 1207: 1204: 1194:-element set 1193: 1174: 1168: 1162: 1156: 1153: 1150: 1144: 1141: 1138: 1132: 1126: 1114: 1110: 1107: 1092: 1090: 1084: 1079: 1075: 1070: 1042: 1037: 1032: 1027: 1022: 1017: 1010: 998: 993: 988: 983: 978: 971: 966: 954: 949: 944: 939: 932: 927: 922: 910: 905: 900: 893: 888: 883: 878: 866: 861: 854: 849: 844: 839: 834: 822: 815: 810: 805: 800: 795: 790: 772: 771: 770: 767: 763: 759: 753: 746: 743: 738: 734: 730: 726: 721: 717: 711: 707: 703: 698: 694: 690: 683: 676: 670: 665: 661: 651: 649: 643: 639: 634: 628: 624: 620: 616: 612: 608: 604: 599: 597: 593: 589: 585: 580: 576: 569: 565: 558: 554: 548: 544: 537: 533: 529: 523: 518: 514: 506: 502: 494: 490: 485: 481: 477: 473: 468: 463: 459: 455: 449: 445: 440: 436: 430: 426: 421: 417: 412: 409: 405: 399: 395: 389: 385: 380: 376: 369: 364: 359: 355: 336: 328: 324: 320: 315: 311: 307: 304: 301: 298: 289: 284: 276: 270: 255: 247: 241: 238: 235: 232: 227: 219: 213: 207: 201: 195: 188: 187: 186: 184: 180: 174: 169: 165: 161: 156: 152: 145: 141: 137: 118: 115: 112: 109: 106: 103: 97: 94: 91: 85: 82: 79: 76: 73: 66: 65: 64: 56: 54: 49: 47: 43: 39: 35: 31: 27: 23: 22:combinatorics 19: 2404:Permutations 2381: 2373:the original 2368: 2357:Bibliography 2328: 2324: 2315: 2306: 2302: 2292: 2283: 2279: 2273: 2236: 2219: 2215: 2210: 2207: 2203: 2190:(unsigned). 2181: 2064: 2062: 1947: 1740: 1738: 1559: 1551: 1543: 1541: 1388: 1348: 1344: 1340: 1336: 1334: 1329: 1322: 1315: 1311: 1307: 1303: 1292: 1290: 1267: 1262: 1258: 1253: 1249: 1191: 1112: 1108: 1103: 1088: 1082: 1077: 1073: 1071: 1068: 765: 761: 757: 751: 747: 741: 736: 732: 728: 724: 719: 715: 709: 705: 701: 696: 692: 681: 674: 668: 663: 659: 657: 647: 641: 637: 632: 626: 622: 618: 614: 610: 609:) for fixed 606: 602: 600: 595: 587: 583: 582:at position 578: 574: 567: 563: 556: 552: 546: 542: 535: 527: 521: 516: 512: 504: 500: 492: 488: 483: 479: 475: 471: 466: 461: 457: 453: 447: 443: 438: 434: 428: 424: 419: 415: 413: 407: 403: 397: 393: 387: 383: 378: 374: 367: 362: 357: 353: 351: 178: 172: 167: 163: 159: 154: 150: 143: 139: 135: 133: 62: 50: 37: 25: 15: 2241:. See also 2220:Allegedly, 2182:(using the 1739:Indeed, as 1302:, there is 1277:independent 34:permutation 26:Lehmer code 18:mathematics 2393:Categories 2265:References 2211:a fortiori 1310:) at rank 2309:: 176–183 2286:: 179–193 2155:¯ 2096:∏ 2031:− 1910:− 1690:≤ 1684:≤ 1677:∑ 1667:ω 1612:≤ 1606:≤ 1599:∑ 1589:ω 1519:− 1507:ω 1489:⇔ 1471:∈ 1468:ω 1443:ω 1425:⇔ 1407:∈ 1404:ω 1226:− 1217:… 1169:× 1157:× 1154:⋯ 1151:× 1142:− 1133:× 325:σ 312:σ 293:# 277:σ 248:σ 236:… 220:σ 202:σ 183:encodings 116:× 110:× 107:⋯ 104:× 95:− 86:× 46:inversion 1347:", i.e. 59:The code 2347:2245639 1550:(resp. 1339:(resp. 1308:maximum 1306:(resp. 723:, and ( 541:, ..., 478:) with 422:) with 373:, ..., 149:, ..., 48:table. 2345:  2141:  2135:  1752:  1698:  1620:  1360:  1330:i>k 511:+ … + 456:, and 406:+ 1 − 30:encode 24:, the 2343:JSTOR 1328:with 1299:1≤k≤n 718:> 619:value 442:> 427:< 266:where 179:every 1993:is 1948:The 1741:L(k) 1349:B(k) 1341:H(k) 1337:B(k) 1335:Let 1293:u=(u 432:and 321:< 302:> 2333:doi 2070:is 1649:and 1556:(ω) 1548:(ω) 1460:and 1314:if 1248:on 1085:− 1 754:− 1 745:.) 684:− 2 677:− 1 175:− 1 16:In 2395:: 2367:, 2341:, 2327:, 2307:16 2301:, 2284:10 2282:, 2245:. 1283:. 577:− 499:+ 396:− 2335:: 2329:4 2165:! 2162:n 2152:n 2147:s 2138:= 2132:) 2129:s 2126:( 2121:k 2117:G 2111:n 2106:1 2103:= 2100:k 2092:= 2089:) 2086:s 2083:( 2080:G 2067:b 2065:N 2049:, 2044:k 2040:s 2037:+ 2034:1 2028:k 2022:= 2019:) 2016:s 2013:( 2008:k 2004:G 1979:) 1976:k 1973:( 1970:B 1966:1 1960:1 1934:. 1928:k 1925:1 1919:= 1916:) 1913:1 1907:k 1904:= 1901:) 1898:k 1895:( 1892:L 1889:( 1885:P 1881:= 1878:) 1875:) 1872:k 1869:( 1866:H 1863:( 1859:P 1855:= 1852:) 1849:0 1846:= 1843:) 1840:k 1837:( 1834:L 1831:( 1827:P 1823:= 1820:) 1817:) 1814:k 1811:( 1808:B 1805:( 1801:P 1778:, 1775:] 1771:] 1768:k 1765:, 1762:1 1759:[ 1755:[ 1725:. 1720:) 1717:k 1714:( 1711:H 1707:1 1701:1 1693:n 1687:k 1681:1 1673:= 1670:) 1664:( 1659:b 1655:N 1642:) 1639:k 1636:( 1633:B 1629:1 1623:1 1615:n 1609:k 1603:1 1595:= 1592:) 1586:( 1581:b 1577:N 1560:ω 1554:h 1552:N 1546:b 1544:N 1528:. 1525:} 1522:1 1516:k 1513:= 1510:) 1504:, 1501:k 1498:( 1495:L 1492:{ 1486:} 1483:) 1480:k 1477:( 1474:H 1465:{ 1455:} 1452:0 1449:= 1446:) 1440:, 1437:k 1434:( 1431:L 1428:{ 1422:} 1419:) 1416:k 1413:( 1410:B 1401:{ 1389:k 1372:n 1366:S 1345:k 1325:i 1323:u 1318:k 1316:u 1312:k 1297:) 1295:k 1268:i 1265:) 1263:σ 1261:( 1259:L 1254:n 1250:S 1232:} 1229:1 1223:k 1220:, 1214:, 1211:1 1208:, 1205:0 1202:{ 1192:k 1178:] 1175:1 1172:[ 1166:] 1163:2 1160:[ 1148:] 1145:1 1139:n 1136:[ 1130:] 1127:n 1124:[ 1113:n 1109:S 1089:n 1083:n 1078:x 1074:x 1049:0 1043:1 1038:1 1033:3 1028:0 1023:4 1018:1 1011:0 1005:1 999:1 994:3 989:0 984:4 979:1 972:0 967:2 961:1 955:3 950:0 945:4 940:1 933:0 928:2 923:1 917:3 911:0 906:4 901:1 894:1 889:3 884:2 879:4 873:0 867:4 862:1 855:1 850:3 845:2 840:5 835:0 829:4 823:1 816:2 811:4 806:3 801:6 796:0 791:5 785:1 766:x 762:x 758:x 752:n 742:i 739:) 737:σ 735:( 733:L 729:j 727:, 725:i 720:i 716:j 710:i 706:σ 702:i 697:i 693:σ 682:n 675:n 669:n 664:n 660:n 648:σ 642:j 638:σ 633:i 627:j 623:σ 615:i 611:j 607:j 605:, 603:i 596:n 588:σ 584:i 579:i 575:n 568:j 564:σ 557:i 553:σ 547:n 543:σ 539:1 536:σ 528:σ 522:n 519:) 517:σ 515:( 513:L 509:2 507:) 505:σ 503:( 501:L 497:1 495:) 493:σ 491:( 489:L 484:j 480:i 476:j 474:, 472:i 467:i 464:) 462:σ 460:( 458:L 454:σ 448:j 444:σ 439:i 435:σ 429:j 425:i 420:j 418:, 416:i 408:i 404:n 398:i 394:n 388:i 384:σ 379:n 375:σ 371:1 368:σ 363:i 360:) 358:σ 356:( 354:L 337:, 334:} 329:i 316:j 308:: 305:i 299:j 296:{ 290:= 285:i 281:) 274:( 271:L 261:) 256:n 252:) 245:( 242:L 239:, 233:, 228:1 224:) 217:( 214:L 211:( 208:= 205:) 199:( 196:L 173:n 168:n 164:n 160:n 155:n 151:σ 147:1 144:σ 140:σ 136:n 119:1 113:2 101:) 98:1 92:n 89:( 83:n 80:= 77:! 74:n 38:n

Index

mathematics
combinatorics
encode
permutation
numbering permutations
inversion
Derrick Henry Lehmer
encodings
lexicographical order
factorial number system
total ordering
symmetric group
uniform distribution
random variable
independent
Cartesian product
Bernoulli random variables
generating function
rising factorial
Stirling numbers of the first kind
Secretary problem
Johannes Kepler
secretary problem
Wolfram Alpha
Inversion (discrete mathematics) § Inversion related vectors
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Mathematics portal
"Sur la numération factorielle, application aux permutations"
Ferguson, Thomas S.
doi

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