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Presentation of a group

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The following table lists some examples of presentations for commonly studied groups. Note that in each case there are many other presentations that are possible. The presentation listed is not necessarily the most efficient one possible.
4908: 3577: 3153: 3474: 3050: 4379: 2610: 4618: 824: 957: 397: 1062: 4010: 3913: 3816: 3719: 2390: 4107: 4711: 4207: 2791: 1874:. In this perspective, we declare two words to be equivalent if it is possible to get from one to the other by a sequence of moves, where each move consists of adding or removing a consecutive pair 2481: 2119:
states that a finitely generated group has a recursive presentation if and only if it can be embedded in a finitely presented group. From this we can deduce that there are (up to isomorphism) only
3226: 4469: 2228: 3387: 2925: 1417: 223: 2687: 4956: 271: 2289: 2001:) if it has a presentation that is finitely generated (respectively finitely related, a finite presentation). A group which has a finite presentation with a single relation is called a 118: 2838: 1540: 1504: 1460: 1355: 1254: 1774: 3619: 3267: 2966: 1824: 5646: 1872: 1620: 1938: 1905: 1665: 1089:
used in this article for a presentation is now the most common, earlier writers used different variations on the same format. Such notations include the following:
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Every group has a presentation, and in fact many different presentations; a presentation is often the most compact way of describing the structure of the group.
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Every finitely presented group is recursively presented, but there are recursively presented groups that cannot be finitely presented. However a theorem of
3397: 2973: 4240: 1948:, or by adding or removing a consecutive copy of a relator. The group elements are the equivalence classes, and the group operation is concatenation. 5595: 2503: 5869: 5625: 4508: 276:
thanks to the convention that terms that do not include an equals sign are taken to be equal to the group identity. Such terms are called
728: 5921: 873: 5876:― fundamental algorithms from theoretical computer science, computational number theory, and computational commutative algebra, etc. 5838: 5815: 5771: 316: 984: 3935: 3838: 3741: 3644: 2315: 4030: 287: 4642: 5926: 4131: 2720: 2131:
many non-isomorphic two generator groups. Therefore, there are finitely generated groups that cannot be recursively presented.
5799: 5846: 5737: 2419: 5672: 5154: 3164: 1288: 156: 4416: 5853: 2201: 3340: 2878: 1366: 4635: 5822:― This useful reference has tables of presentations of all small finite groups, the reflection groups, and so forth. 180: 5763: 2642: 2160: 1952: 4931: 234: 2255: 66: 70:—so that every element of the group can be written as a product of powers of some of these generators—and a set 5803: 5457: 5452: 5249: 4922: 1965: 1156: 37:
This article is about specifying generators and relations of a group. For describing a module over a ring, see
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One of the earliest presentations of a group by generators and relations was given by the Irish mathematician
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An even shorter form drops the equality and identity signs, to list just the set of relators, which is
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Informally, we can consider these products on the left hand side as being elements of the free group
31: 5826: 5352: 1186: 53: 1841: 1586: 5556: 4998: 4994: 3583:
Note the similarity with the symmetric group; the only difference is the removal of the relation
2800: 5520: 2026: 2104:. This usage may seem odd, but it is possible to prove that if a group has a presentation with 5865: 5834: 5811: 5767: 5721: 5621: 5617: 5548: 3734: 2148: 1835: 140: 38: 4903:{\displaystyle \langle a,b\mid a^{2},b^{3},(ab)^{13},^{5},^{4},((ab)^{4}ab^{-1})^{6}\rangle } 1910: 1877: 1637: 5777: 5729: 5711: 5701: 5655: 5540: 5501: 5492:
Peifer, David (1997). "An Introduction to Combinatorial Group Theory and the Word Problem".
5435: 5023: 4501: 4023: 3831: 2615: 2152: 2144: 2124: 3572:{\displaystyle \sigma _{i}\sigma _{i+1}\sigma _{i}=\sigma _{i+1}\sigma _{i}\sigma _{i+1}\ } 3148:{\displaystyle \sigma _{i}\sigma _{i+1}\sigma _{i}=\sigma _{i+1}\sigma _{i}\sigma _{i+1}\ } 1689: 1301: 1259: 1200: 5781: 5733: 5659: 4392: 2865: 5845:― Schreier's method, Nielsen's method, free presentations, subgroups and HNN extensions, 1548: 526:. Each such product equivalence can be expressed as an equality to the identity, such as 5697: 5536: 5525:
Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences
5892: 5858: 4926: 2496: 2304: 1358: 706: 462: 144: 5716: 3469:{\displaystyle \sigma _{i}\sigma _{j}=\sigma _{j}\sigma _{i}{\mbox{ if }}j\neq i\pm 1} 3045:{\displaystyle \sigma _{i}\sigma _{j}=\sigma _{j}\sigma _{i}{\mbox{ if }}j\neq i\pm 1} 5915: 5755: 5641: 5560: 5428: 5424: 5150: 4409: 3637: 2116: 2073: 2025:
or a finite subset of them, then it is easy to set up a simple one to one coding (or
431:, subject only to canceling a generator with an adjacent occurrence of its inverse. 5505: 5419: 5402: 5386: 5211: 5106: 4478: 4374:{\displaystyle \langle a,b,j\mid aba=bab,(aba)^{4},j^{2},(ja)^{2},(jb)^{2}\rangle } 2244: 1679: 167: 427:
may be zero). In less formal terms, the group consists of words in the generators
17: 5676: 5644:(1955), "On the algorithmic unsolvability of the word problem in group theory", 5410: 5392: 3332: 2156: 2128: 45: 5754:
Johnson, D.L.; Robertson, E.L. (1979). "Finite groups of deficiency zero". In
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The definition of group presentation may alternatively be recast in terms of
5897: 5706: 2120: 5725: 5544: 2605:{\displaystyle \langle r,f\mid r^{2n},r^{n}=f^{2},frf^{-1}=r^{-1}\rangle } 4959: 280:, distinguishing them from the relations that do include an equals sign. 2232:
A free group is "free" in the sense that it is subject to no relations.
617:, each of which is also equivalent to 1 when considered as products in D 4613:{\displaystyle \langle x,y,z\mid z=xyx^{-1}y^{-1},xz=zx,yz=zy\rangle } 2050:
to the natural numbers, such that we can find algorithms that, given
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where 1 is the group identity. This may be written equivalently as
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has the above presentation if it is the "freest group" generated by
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are supposed to be equal in the quotient group. Thus, for example,
819:{\displaystyle \langle r,f\mid r^{8}=1,f^{2}=1,(rf)^{2}=1\rangle .} 450:
is also of the above form; but in general, these products will not
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A presentation of a group determines a geometry, in the sense of
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Specification of a mathematical group by generators and relations
952:{\displaystyle \langle r,f\mid r^{8}=f^{2}=(rf)^{2}=1\rangle .} 685:
of members of such conjugates. It follows that each element of
5438:) are intrinsic, meaning independent of choice of generators. 5347:), is the maximum of the deficiency over all presentations of 5105:
One may take the elements of the group for generators and the
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by the smallest normal subgroup that contains each element of
392:{\displaystyle s_{1}^{a_{1}}s_{2}^{a_{2}}\cdots s_{n}^{a_{n}}} 1057:{\displaystyle \langle r,f\mid r^{8},f^{2},(rf)^{2}\rangle .} 4005:{\displaystyle \langle s,t\mid s^{2},t^{3},(st)^{5}\rangle } 3908:{\displaystyle \langle s,t\mid s^{2},t^{3},(st)^{4}\rangle } 3811:{\displaystyle \langle s,t\mid s^{2},t^{3},(st)^{3}\rangle } 3714:{\displaystyle \langle s,t\mid s^{2},t^{2},(st)^{2}\rangle } 2385:{\displaystyle \langle r,f\mid r^{n},f^{2},(rf)^{2}\rangle } 5149:
describe the same element in the group. This was shown by
4102:{\displaystyle \langle i,j\mid i^{4},jij=i,iji=j\rangle \,} 5351:. The deficiency of a finite group is non-positive. The 4706:{\displaystyle \langle a,b\mid a^{n}=ba^{m}b^{-1}\rangle } 1951:
This point of view is particularly common in the field of
4202:{\displaystyle \langle a,b\mid aba=bab,(aba)^{4}\rangle } 2786:{\displaystyle \langle x,y\mid x^{m},y^{n},xy=yx\rangle } 2088:) is recursive (respectively recursively enumerable). If 5906: 5864:(1st ed.). Cambridge: Cambridge University Press. 5833:(2nd ed.). Cambridge: Cambridge University Press. 5133:
for which there is no algorithm which, given two words
5579:"Memorandum respecting a new System of Roots of Unity" 5086:. This presentation may be highly inefficient if both 3445: 3021: 2476:{\displaystyle \langle r,f\mid f^{2},(rf)^{2}\rangle } 2123:
many finitely generated recursively presented groups.
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It is a common practice to write relators in the form
643:, then it follows by definition that every element of 286:
A closely related but different concept is that of an
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recursively enumerable then it has another one with
1622:. This has the intuitive meaning that the images of 5647:
Proceedings of the Steklov Institute of Mathematics
4464:{\displaystyle \langle a,b\mid a^{2},b^{3}\rangle } 3158:The last set of relations can be transformed into 2174: 2096:recursively enumerable, then the presentation is a 5907:Small groups and their presentations on GroupNames 5857: 4950: 4902: 4705: 4612: 4463: 4373: 4201: 4101: 4004: 3907: 3810: 3713: 3613: 3571: 3468: 3381: 3261: 3220: 3147: 3044: 2960: 2919: 2832: 2785: 2681: 2604: 2475: 2384: 2283: 2223:{\displaystyle \langle S\mid \varnothing \rangle } 2222: 1932: 1899: 1866: 1818: 1768: 1705: 1659: 1614: 1563: 1534: 1498: 1454: 1411: 1349: 1317: 1275: 1248: 1216: 1056: 951: 818: 391: 310:described as a finite length product of the form: 265: 217: 112: 3382:{\displaystyle \sigma _{1},\ldots ,\sigma _{n-1}} 2920:{\displaystyle \sigma _{1},\ldots ,\sigma _{n-1}} 2159:, in the early 1880s, laying the foundations for 1981:is finite. If both are finite it is said to be a 469:of order sixteen can be generated by a rotation, 1412:{\displaystyle \langle S\mid R\rangle =F_{S}/N.} 139:is said to have the above presentation if it is 5685:Proceedings of the National Academy of Sciences 5037:, therefore is equal to its normal closure, so 5153:in 1955 and a different proof was obtained by 1155:"Relator" redirects here. For other uses, see 218:{\displaystyle \langle a\mid a^{n}=1\rangle ,} 5101:Every finite group has a finite presentation. 2682:{\displaystyle \langle x,y\mid xy=yx\rangle } 8: 5808:Generators and Relations for Discrete Groups 5434:Further, some properties of this graph (the 5121:states that there is a finite presentation 4951:{\displaystyle \mathbf {Z} \wr \mathbf {Z} } 4897: 4730: 4700: 4646: 4607: 4512: 4458: 4420: 4368: 4244: 4196: 4135: 4095: 4034: 3999: 3939: 3902: 3842: 3805: 3745: 3708: 3648: 2827: 2815: 2780: 2724: 2676: 2646: 2599: 2507: 2470: 2423: 2379: 2319: 2278: 2259: 2217: 2205: 2062:, and vice versa. We can then call a subset 1674:, it is possible to build a presentation of 1529: 1517: 1493: 1481: 1449: 1437: 1382: 1370: 1344: 1332: 1243: 1231: 1048: 988: 943: 877: 810: 732: 477:, of order 2; and certainly any element of D 266:{\displaystyle \langle a\mid a^{n}\rangle ,} 257: 238: 209: 184: 104: 92: 5413:. These are also two resulting orders, the 2284:{\displaystyle \langle a\mid a^{n}\rangle } 1634:in the list of relators is equivalent with 5860:Computation with Finitely Presented Groups 2151:. The first systematic study was given by 5715: 5705: 4943: 4935: 4933: 4891: 4878: 4865: 4840: 4809: 4784: 4762: 4749: 4728: 4691: 4681: 4665: 4644: 4562: 4549: 4510: 4452: 4439: 4418: 4362: 4340: 4318: 4305: 4242: 4190: 4133: 4098: 4053: 4032: 3993: 3971: 3958: 3937: 3896: 3874: 3861: 3840: 3799: 3777: 3764: 3743: 3702: 3680: 3667: 3646: 3599: 3594: 3588: 3554: 3544: 3528: 3515: 3499: 3489: 3483: 3444: 3438: 3428: 3415: 3405: 3399: 3367: 3348: 3342: 3247: 3242: 3236: 3203: 3186: 3176: 3168: 3166: 3130: 3120: 3104: 3091: 3075: 3065: 3059: 3020: 3014: 3004: 2991: 2981: 2975: 2946: 2941: 2935: 2905: 2886: 2880: 2813: 2756: 2743: 2722: 2644: 2590: 2574: 2555: 2542: 2526: 2505: 2464: 2442: 2421: 2373: 2351: 2338: 2317: 2272: 2257: 2203: 1918: 1912: 1888: 1879: 1855: 1843: 1826:is an entry in the multiplication table. 1810: 1797: 1787: 1781: 1757: 1752: 1742: 1732: 1726: 1697: 1691: 1645: 1639: 1594: 1588: 1550: 1515: 1479: 1435: 1398: 1392: 1368: 1330: 1309: 1303: 1267: 1261: 1229: 1208: 1202: 1042: 1020: 1007: 986: 931: 909: 896: 875: 798: 770: 751: 730: 693:, will also evaluate to 1; and thus that 602:be the subgroup generated by the strings 381: 376: 371: 356: 351: 346: 334: 329: 324: 318: 251: 236: 197: 182: 90: 5521:"Subgroups of finitely presented groups" 5487: 5485: 5483: 5059:. Since the identity map is surjective, 1067:All three presentations are equivalent. 113:{\displaystyle \langle S\mid R\rangle .} 5479: 5282:, where means that every element from 4111:For an alternative presentation see Dic 2833:{\displaystyle \langle S\mid R\rangle } 2214: 1535:{\displaystyle \langle S\mid R\rangle } 1499:{\displaystyle \langle S\mid R\rangle } 1455:{\displaystyle \langle S\mid R\rangle } 1350:{\displaystyle \langle S\mid R\rangle } 1249:{\displaystyle \langle S\mid R\rangle } 4997:of free groups, there exists a unique 4925:that is not finitely presented is the 2021:consisting of all the natural numbers 978:. Doing this gives the presentation 867:abbreviated, giving the presentation 306:is a group where each element can be 7: 1769:{\displaystyle g_{i}g_{j}g_{k}^{-1}} 1224:. To form a group with presentation 78:among those generators. We then say 689:, when considered as a product in D 3282:is the permutation that swaps the 25: 5427:. An important example is in the 5286:commutes with every element from 3614:{\displaystyle \sigma _{i}^{2}=1} 3262:{\displaystyle \sigma _{i}^{2}=1} 2961:{\displaystyle \sigma _{i}^{2}=1} 1474:is said to have the presentation 5601:from the original on 2003-06-26. 5094:are much larger than necessary. 4944: 4936: 1819:{\displaystyle g_{i}g_{j}=g_{k}} 1287:. (This subgroup is called the 288:absolute presentation of a group 5743:from the original on 2015-09-24 4974:Every group has a presentation. 2100:and the corresponding group is 844:}, and the set of relations is 498:However, we have, for example, 5506:10.1080/0025570X.1997.11996491 5339:of a finitely presented group 5063:is also surjective, so by the 4888: 4862: 4852: 4849: 4837: 4818: 4806: 4793: 4781: 4771: 4359: 4349: 4337: 4327: 4302: 4289: 4187: 4174: 3990: 3980: 3893: 3883: 3796: 3786: 3699: 3689: 3200: 3169: 2461: 2451: 2370: 2360: 1039: 1029: 928: 918: 829:Here the set of generators is 795: 785: 131:subject only to the relations 52:is one method of specifying a 1: 5810:. New York: Springer-Verlag. 5117:The negative solution to the 1963:A presentation is said to be 518:, etc., so such products are 5371:if this number is required. 2009:Recursively presented groups 1867:{\displaystyle S\cup S^{-1}} 1721:to be all words of the form 1615:{\displaystyle y^{-1}x\in R} 1197:naturally gives a subset of 632:generated by all conjugates 409:are elements of S, adjacent 157:normal subgroup generated by 56:. A presentation of a group 5614:Mathematics and its history 5026:of this homomorphism. Then 4978:To see this, given a group 423:are non-zero integers (but 5943: 5922:Combinatorial group theory 5764:Cambridge University Press 5575:Sir William Rowan Hamilton 5390: 5384: 5378: 4982:, consider the free group 2398:represents a rotation and 2161:combinatorial group theory 1953:combinatorial group theory 1680:group multiplication table 1583:. What this means is that 1154: 473:, of order 8; and a flip, 442:is a generating subset of 36: 29: 5847:Golod–Shafarevich theorem 5519:Higman, G. (1961-08-08). 5359:can be generated by −def( 5307:of a finite presentation 5065:First Isomorphism Theorem 5018:is the identity map. Let 3308:is a 3-cycle on the set { 2127:has shown that there are 1959:Finitely presented groups 1838:of words on the alphabet 166:As a simple example, the 5760:Homological Group Theory 5612:Stillwell, John (2002). 5458:Presentation of a monoid 5453:Presentation of a module 4923:finitely generated group 2147:– a presentation of the 2092:is indexed as above and 1157:Relator (disambiguation) 697:is a normal subgroup of 446:, then every element of 30:Not to be confused with 5831:Presentations of Groups 5707:10.1073/pnas.44.10.1061 5119:word problem for groups 4636:Baumslag–Solitar groups 2622:is a special case when 2413:infinite dihedral group 2046:from the free group on 1933:{\displaystyle x^{-1}x} 1900:{\displaystyle xx^{-1}} 1686:to be the set elements 1660:{\displaystyle r^{n}=1} 1357:is then defined as the 1256:, take the quotient of 454:describe an element of 5927:Combinatorics on words 5587:Philosophical Magazine 5545:10.1098/rspa.1961.0132 5448:Nielsen transformation 5399:geometric group theory 5381:Geometric group theory 5375:Geometric group theory 5103: 4976: 4952: 4904: 4707: 4614: 4465: 4375: 4203: 4103: 4006: 3909: 3812: 3715: 3615: 3573: 3470: 3383: 3290:+1st one. The product 3263: 3222: 3149: 3046: 2962: 2921: 2834: 2787: 2683: 2606: 2477: 2386: 2285: 2224: 2141:William Rowan Hamilton 2098:recursive presentation 2078:recursively enumerable 1934: 1901: 1868: 1820: 1770: 1707: 1661: 1616: 1565: 1536: 1500: 1456: 1413: 1351: 1319: 1277: 1250: 1218: 1075:Although the notation 1058: 953: 820: 393: 267: 219: 135:. Formally, the group 114: 5468:Tietze transformation 5391:Further information: 5385:Further information: 5205:being disjoint. Then 5113:Novikov–Boone theorem 5096: 5014:whose restriction to 4969: 4953: 4905: 4708: 4615: 4481:of the cyclic groups 4466: 4376: 4219:can be visualized as 4204: 4104: 4007: 3910: 3813: 3716: 3616: 3574: 3471: 3384: 3264: 3223: 3150: 3047: 2963: 2922: 2835: 2788: 2684: 2607: 2478: 2387: 2286: 2225: 2102:recursively presented 1935: 1902: 1869: 1821: 1771: 1708: 1706:{\displaystyle g_{i}} 1662: 1617: 1566: 1537: 1501: 1457: 1414: 1352: 1320: 1318:{\displaystyle F_{S}} 1278: 1276:{\displaystyle F_{S}} 1251: 1219: 1217:{\displaystyle F_{S}} 1059: 954: 821: 705:is isomorphic to the 394: 268: 220: 174:has the presentation 115: 5893:"Group Presentation" 5766:. pp. 275–289. 5616:. Springer. p.  5494:Mathematics Magazine 5463:Set-builder notation 5423:, and corresponding 4932: 4727: 4643: 4509: 4417: 4241: 4132: 4031: 3936: 3839: 3742: 3645: 3587: 3482: 3398: 3341: 3286:th element with the 3235: 3165: 3058: 2974: 2934: 2879: 2812: 2721: 2643: 2504: 2420: 2316: 2256: 2202: 2017:is indexed by a set 1911: 1878: 1842: 1830:Alternate definition 1780: 1725: 1690: 1638: 1587: 1549: 1514: 1478: 1462:and the elements of 1434: 1367: 1329: 1302: 1260: 1228: 1201: 985: 874: 729: 718:. We then say that D 647:is a finite product 317: 235: 181: 89: 32:Group representation 5698:1958PNAS...44.1061B 5537:1961RSPSA.262..455H 5353:Schur multiplicator 3604: 3252: 2951: 1983:finite presentation 1836:equivalence classes 1765: 1682:, as follows. Take 1670:For a finite group 1564:{\displaystyle x=y} 628:be the subgroup of 598:. That is, we let 388: 363: 341: 5889:de Cornulier, Yves 5677:"The word problem" 5363:) generators, and 5355:of a finite group 5141:, decides whether 4999:group homomorphism 4995:universal property 4948: 4900: 4703: 4610: 4461: 4371: 4199: 4099: 4002: 3905: 3808: 3711: 3611: 3590: 3569: 3466: 3449: 3379: 3259: 3238: 3218: 3145: 3042: 3025: 2958: 2937: 2917: 2844:is the set of all 2830: 2801:free abelian group 2783: 2679: 2602: 2473: 2382: 2281: 2220: 1997:finitely presented 1987:finitely generated 1966:finitely generated 1930: 1897: 1864: 1816: 1766: 1748: 1703: 1657: 1612: 1561: 1532: 1496: 1452: 1409: 1347: 1315: 1273: 1246: 1214: 1054: 949: 816: 438:is any group, and 429:and their inverses 416:are distinct, and 389: 367: 342: 320: 263: 215: 110: 18:Group presentation 5871:978-0-521-13507-8 5800:Coxeter, H. S. M. 5692:(10): 1061–1065, 5673:Boone, William W. 5642:Novikov, Pyotr S. 5627:978-0-387-95336-6 5531:(1311): 455–475. 5262:has presentation 5224:has presentation 5185:has presentation 5169:has presentation 4919: 4918: 3929:icosahedral group 3735:tetrahedral group 3568: 3448: 3217: 3144: 3024: 2149:icosahedral group 2003:one-relator group 1510:is isomorphic to 1166:be a set and let 722:has presentation 461:For example, the 82:has presentation 39:free presentation 16:(Redirected from 5934: 5903: 5902: 5875: 5863: 5854:Sims, Charles C. 5844: 5821: 5786: 5785: 5751: 5745: 5744: 5742: 5719: 5709: 5681: 5669: 5663: 5662: 5638: 5632: 5631: 5609: 5603: 5602: 5600: 5583: 5571: 5565: 5564: 5516: 5510: 5509: 5489: 5334: 5332: 5326: 5318: 5281: 5261: 5243: 5223: 5196: 5180: 5132: 5085: 5058: 5013: 4958:of the group of 4957: 4955: 4954: 4949: 4947: 4939: 4921:An example of a 4909: 4907: 4906: 4901: 4896: 4895: 4886: 4885: 4870: 4869: 4845: 4844: 4814: 4813: 4789: 4788: 4767: 4766: 4754: 4753: 4712: 4710: 4709: 4704: 4699: 4698: 4686: 4685: 4670: 4669: 4619: 4617: 4616: 4611: 4570: 4569: 4557: 4556: 4502:Heisenberg group 4470: 4468: 4467: 4462: 4457: 4456: 4444: 4443: 4380: 4378: 4377: 4372: 4367: 4366: 4345: 4344: 4323: 4322: 4310: 4309: 4208: 4206: 4205: 4200: 4195: 4194: 4117:above with n=2. 4108: 4106: 4105: 4100: 4058: 4057: 4024:quaternion group 4011: 4009: 4008: 4003: 3998: 3997: 3976: 3975: 3963: 3962: 3926: 3914: 3912: 3911: 3906: 3901: 3900: 3879: 3878: 3866: 3865: 3832:octahedral group 3829: 3817: 3815: 3814: 3809: 3804: 3803: 3782: 3781: 3769: 3768: 3732: 3720: 3718: 3717: 3712: 3707: 3706: 3685: 3684: 3672: 3671: 3635: 3620: 3618: 3617: 3612: 3603: 3598: 3578: 3576: 3575: 3570: 3566: 3565: 3564: 3549: 3548: 3539: 3538: 3520: 3519: 3510: 3509: 3494: 3493: 3475: 3473: 3472: 3467: 3450: 3446: 3443: 3442: 3433: 3432: 3420: 3419: 3410: 3409: 3388: 3386: 3385: 3380: 3378: 3377: 3353: 3352: 3268: 3266: 3265: 3260: 3251: 3246: 3227: 3225: 3224: 3219: 3215: 3208: 3207: 3198: 3197: 3196: 3181: 3180: 3154: 3152: 3151: 3146: 3142: 3141: 3140: 3125: 3124: 3115: 3114: 3096: 3095: 3086: 3085: 3070: 3069: 3051: 3049: 3048: 3043: 3026: 3022: 3019: 3018: 3009: 3008: 2996: 2995: 2986: 2985: 2967: 2965: 2964: 2959: 2950: 2945: 2926: 2924: 2923: 2918: 2916: 2915: 2891: 2890: 2839: 2837: 2836: 2831: 2792: 2790: 2789: 2784: 2761: 2760: 2748: 2747: 2688: 2686: 2685: 2680: 2616:quaternion group 2611: 2609: 2608: 2603: 2598: 2597: 2582: 2581: 2560: 2559: 2547: 2546: 2534: 2533: 2482: 2480: 2479: 2474: 2469: 2468: 2447: 2446: 2391: 2389: 2388: 2383: 2378: 2377: 2356: 2355: 2343: 2342: 2290: 2288: 2287: 2282: 2277: 2276: 2229: 2227: 2226: 2221: 2175: 2153:Walther von Dyck 2145:icosian calculus 2143:in 1856, in his 2125:Bernhard Neumann 2045: 1999: 1998: 1991:finitely related 1975:finitely related 1947: 1943: 1939: 1937: 1936: 1931: 1926: 1925: 1906: 1904: 1903: 1898: 1896: 1895: 1873: 1871: 1870: 1865: 1863: 1862: 1825: 1823: 1822: 1817: 1815: 1814: 1802: 1801: 1792: 1791: 1775: 1773: 1772: 1767: 1764: 1756: 1747: 1746: 1737: 1736: 1712: 1710: 1709: 1704: 1702: 1701: 1666: 1664: 1663: 1658: 1650: 1649: 1621: 1619: 1618: 1613: 1602: 1601: 1570: 1568: 1567: 1562: 1541: 1539: 1538: 1533: 1505: 1503: 1502: 1497: 1461: 1459: 1458: 1453: 1422:The elements of 1418: 1416: 1415: 1410: 1402: 1397: 1396: 1356: 1354: 1353: 1348: 1324: 1322: 1321: 1316: 1314: 1313: 1282: 1280: 1279: 1274: 1272: 1271: 1255: 1253: 1252: 1247: 1223: 1221: 1220: 1215: 1213: 1212: 1146: 1145: 1130: 1118: 1105: 1104: 1088: 1087: 1063: 1061: 1060: 1055: 1047: 1046: 1025: 1024: 1012: 1011: 977: 958: 956: 955: 950: 936: 935: 914: 913: 901: 900: 863:. We often see 862: 843: 825: 823: 822: 817: 803: 802: 775: 774: 756: 755: 717: 616: 597: 595: 575: 556: 554: 544: 535: 517: 507: 494: 487: 481:is a product of 398: 396: 395: 390: 387: 386: 385: 375: 362: 361: 360: 350: 340: 339: 338: 328: 272: 270: 269: 264: 256: 255: 224: 222: 221: 216: 202: 201: 119: 117: 116: 111: 60:comprises a set 21: 5942: 5941: 5937: 5936: 5935: 5933: 5932: 5931: 5912: 5911: 5887: 5886: 5883: 5872: 5852: 5841: 5825: 5818: 5804:Moser, W. O. J. 5798: 5795: 5790: 5789: 5774: 5753: 5752: 5748: 5740: 5679: 5671: 5670: 5666: 5640: 5639: 5635: 5628: 5611: 5610: 5606: 5598: 5581: 5573: 5572: 5568: 5518: 5517: 5513: 5491: 5490: 5481: 5476: 5444: 5436:coarse geometry 5395: 5389: 5383: 5377: 5328: 5327:| − | 5322: 5320: 5308: 5301: 5263: 5253: 5225: 5215: 5186: 5170: 5163: 5122: 5115: 5109:for relations. 5068: 5052: 5038: 5035: 5007: 5001: 4987: 4968: 4930: 4929: 4887: 4874: 4861: 4836: 4805: 4780: 4758: 4745: 4725: 4724: 4687: 4677: 4661: 4641: 4640: 4558: 4545: 4507: 4506: 4448: 4435: 4415: 4414: 4393:group extension 4358: 4336: 4314: 4301: 4239: 4238: 4186: 4130: 4129: 4116: 4049: 4029: 4028: 4021: 3989: 3967: 3954: 3934: 3933: 3925: 3921: 3892: 3870: 3857: 3837: 3836: 3828: 3824: 3795: 3773: 3760: 3740: 3739: 3731: 3727: 3698: 3676: 3663: 3643: 3642: 3634: 3630: 3626: 3585: 3584: 3550: 3540: 3524: 3511: 3495: 3485: 3480: 3479: 3434: 3424: 3411: 3401: 3396: 3395: 3389: 3363: 3344: 3339: 3338: 3330: 3307: 3298: 3281: 3233: 3232: 3199: 3182: 3172: 3163: 3162: 3126: 3116: 3100: 3087: 3071: 3061: 3056: 3055: 3010: 3000: 2987: 2977: 2972: 2971: 2932: 2931: 2927: 2901: 2882: 2877: 2876: 2866:symmetric group 2863: 2848:of elements of 2810: 2809: 2752: 2739: 2719: 2718: 2641: 2640: 2621: 2586: 2570: 2551: 2538: 2522: 2502: 2501: 2494: 2460: 2438: 2418: 2417: 2410: 2369: 2347: 2334: 2314: 2313: 2302: 2268: 2254: 2253: 2242: 2200: 2199: 2169: 2137: 2071: 2039: 2030: 2027:Gödel numbering 2011: 1996: 1995: 1961: 1945: 1941: 1914: 1909: 1908: 1884: 1876: 1875: 1851: 1840: 1839: 1832: 1806: 1793: 1783: 1778: 1777: 1738: 1728: 1723: 1722: 1693: 1688: 1687: 1641: 1636: 1635: 1590: 1585: 1584: 1547: 1546: 1512: 1511: 1476: 1475: 1466:are called the 1432: 1431: 1426:are called the 1388: 1365: 1364: 1327: 1326: 1305: 1300: 1299: 1263: 1258: 1257: 1226: 1225: 1204: 1199: 1198: 1171: 1160: 1153: 1135: 1134: 1121: 1108: 1094: 1093: 1077: 1076: 1073: 1038: 1016: 1003: 983: 982: 963: 927: 905: 892: 872: 871: 845: 830: 794: 766: 747: 727: 726: 721: 709: 704: 692: 683: 677: 671: 665: 659: 653: 624:If we then let 620: 614: 593: 577: 562: 552: 548: 539: 530: 525: 509: 499: 492: 485: 480: 468: 421: 414: 407: 377: 352: 330: 315: 314: 296: 247: 233: 232: 193: 179: 178: 87: 86: 42: 35: 28: 23: 22: 15: 12: 11: 5: 5940: 5938: 5930: 5929: 5924: 5914: 5913: 5910: 5909: 5904: 5882: 5881:External links 5879: 5878: 5877: 5870: 5850: 5839: 5827:Johnson, D. L. 5823: 5816: 5794: 5791: 5788: 5787: 5772: 5746: 5664: 5650:(in Russian), 5633: 5626: 5604: 5566: 5511: 5478: 5477: 5475: 5472: 5471: 5470: 5465: 5460: 5455: 5450: 5443: 5440: 5429:Coxeter groups 5425:Hasse diagrams 5405:, which has a 5401:: one has the 5379:Main article: 5376: 5373: 5343:, denoted def( 5300: 5297: 5296: 5295: 5250:direct product 5245: 5162: 5159: 5114: 5111: 5050: 5033: 5005: 4985: 4967: 4964: 4946: 4942: 4938: 4927:wreath product 4917: 4916: 4910: 4899: 4894: 4890: 4884: 4881: 4877: 4873: 4868: 4864: 4860: 4857: 4854: 4851: 4848: 4843: 4839: 4835: 4832: 4829: 4826: 4823: 4820: 4817: 4812: 4808: 4804: 4801: 4798: 4795: 4792: 4787: 4783: 4779: 4776: 4773: 4770: 4765: 4761: 4757: 4752: 4748: 4744: 4741: 4738: 4735: 4732: 4722: 4716: 4715: 4713: 4702: 4697: 4694: 4690: 4684: 4680: 4676: 4673: 4668: 4664: 4660: 4657: 4654: 4651: 4648: 4638: 4623: 4622: 4620: 4609: 4606: 4603: 4600: 4597: 4594: 4591: 4588: 4585: 4582: 4579: 4576: 4573: 4568: 4565: 4561: 4555: 4552: 4548: 4544: 4541: 4538: 4535: 4532: 4529: 4526: 4523: 4520: 4517: 4514: 4504: 4498: 4497: 4471: 4460: 4455: 4451: 4447: 4442: 4438: 4434: 4431: 4428: 4425: 4422: 4412: 4401: 4400: 4381: 4370: 4365: 4361: 4357: 4354: 4351: 4348: 4343: 4339: 4335: 4332: 4329: 4326: 4321: 4317: 4313: 4308: 4304: 4300: 4297: 4294: 4291: 4288: 4285: 4282: 4279: 4276: 4273: 4270: 4267: 4264: 4261: 4258: 4255: 4252: 4249: 4246: 4236: 4228: 4227: 4211:topologically 4209: 4198: 4193: 4189: 4185: 4182: 4179: 4176: 4173: 4170: 4167: 4164: 4161: 4158: 4155: 4152: 4149: 4146: 4143: 4140: 4137: 4127: 4119: 4118: 4112: 4109: 4097: 4094: 4091: 4088: 4085: 4082: 4079: 4076: 4073: 4070: 4067: 4064: 4061: 4056: 4052: 4048: 4045: 4042: 4039: 4036: 4026: 4019: 4015: 4014: 4012: 4001: 3996: 3992: 3988: 3985: 3982: 3979: 3974: 3970: 3966: 3961: 3957: 3953: 3950: 3947: 3944: 3941: 3931: 3923: 3918: 3917: 3915: 3904: 3899: 3895: 3891: 3888: 3885: 3882: 3877: 3873: 3869: 3864: 3860: 3856: 3853: 3850: 3847: 3844: 3834: 3826: 3821: 3820: 3818: 3807: 3802: 3798: 3794: 3791: 3788: 3785: 3780: 3776: 3772: 3767: 3763: 3759: 3756: 3753: 3750: 3747: 3737: 3729: 3724: 3723: 3721: 3710: 3705: 3701: 3697: 3694: 3691: 3688: 3683: 3679: 3675: 3670: 3666: 3662: 3659: 3656: 3653: 3650: 3640: 3632: 3628: 3623: 3622: 3610: 3607: 3602: 3597: 3593: 3581: 3580: 3579: 3563: 3560: 3557: 3553: 3547: 3543: 3537: 3534: 3531: 3527: 3523: 3518: 3514: 3508: 3505: 3502: 3498: 3492: 3488: 3477: 3465: 3462: 3459: 3456: 3453: 3447: if  3441: 3437: 3431: 3427: 3423: 3418: 3414: 3408: 3404: 3376: 3373: 3370: 3366: 3362: 3359: 3356: 3351: 3347: 3335: 3326: 3322: 3321: 3302: 3294: 3277: 3271: 3258: 3255: 3250: 3245: 3241: 3229: 3228: 3214: 3211: 3206: 3202: 3195: 3192: 3189: 3185: 3179: 3175: 3171: 3156: 3155: 3139: 3136: 3133: 3129: 3123: 3119: 3113: 3110: 3107: 3103: 3099: 3094: 3090: 3084: 3081: 3078: 3074: 3068: 3064: 3053: 3041: 3038: 3035: 3032: 3029: 3023: if  3017: 3013: 3007: 3003: 2999: 2994: 2990: 2984: 2980: 2969: 2957: 2954: 2949: 2944: 2940: 2914: 2911: 2908: 2904: 2900: 2897: 2894: 2889: 2885: 2873: 2859: 2855: 2854: 2852: 2829: 2826: 2823: 2820: 2817: 2807: 2796: 2795: 2793: 2782: 2779: 2776: 2773: 2770: 2767: 2764: 2759: 2755: 2751: 2746: 2742: 2738: 2735: 2732: 2729: 2726: 2716: 2692: 2691: 2689: 2678: 2675: 2672: 2669: 2666: 2663: 2660: 2657: 2654: 2651: 2648: 2638: 2628: 2627: 2619: 2612: 2601: 2596: 2593: 2589: 2585: 2580: 2577: 2573: 2569: 2566: 2563: 2558: 2554: 2550: 2545: 2541: 2537: 2532: 2529: 2525: 2521: 2518: 2515: 2512: 2509: 2499: 2497:dicyclic group 2490: 2486: 2485: 2483: 2472: 2467: 2463: 2459: 2456: 2453: 2450: 2445: 2441: 2437: 2434: 2431: 2428: 2425: 2415: 2408: 2404: 2403: 2392: 2381: 2376: 2372: 2368: 2365: 2362: 2359: 2354: 2350: 2346: 2341: 2337: 2333: 2330: 2327: 2324: 2321: 2311: 2305:dihedral group 2298: 2294: 2293: 2291: 2280: 2275: 2271: 2267: 2264: 2261: 2251: 2238: 2234: 2233: 2230: 2219: 2216: 2213: 2210: 2207: 2197: 2186: 2185: 2182: 2179: 2168: 2165: 2136: 2133: 2076:(respectively 2069: 2037: 2010: 2007: 1989:(respectively 1973:is finite and 1960: 1957: 1929: 1924: 1921: 1917: 1894: 1891: 1887: 1883: 1861: 1858: 1854: 1850: 1847: 1831: 1828: 1813: 1809: 1805: 1800: 1796: 1790: 1786: 1763: 1760: 1755: 1751: 1745: 1741: 1735: 1731: 1700: 1696: 1656: 1653: 1648: 1644: 1611: 1608: 1605: 1600: 1597: 1593: 1560: 1557: 1554: 1531: 1528: 1525: 1522: 1519: 1495: 1492: 1489: 1486: 1483: 1451: 1448: 1445: 1442: 1439: 1420: 1419: 1408: 1405: 1401: 1395: 1391: 1387: 1384: 1381: 1378: 1375: 1372: 1359:quotient group 1346: 1343: 1340: 1337: 1334: 1325:.) The group 1312: 1308: 1289:normal closure 1270: 1266: 1245: 1242: 1239: 1236: 1233: 1211: 1207: 1169: 1152: 1149: 1148: 1147: 1132: 1119: 1106: 1072: 1069: 1065: 1064: 1053: 1050: 1045: 1041: 1037: 1034: 1031: 1028: 1023: 1019: 1015: 1010: 1006: 1002: 999: 996: 993: 990: 960: 959: 948: 945: 942: 939: 934: 930: 926: 923: 920: 917: 912: 908: 904: 899: 895: 891: 888: 885: 882: 879: 827: 826: 815: 812: 809: 806: 801: 797: 793: 790: 787: 784: 781: 778: 773: 769: 765: 762: 759: 754: 750: 746: 743: 740: 737: 734: 719: 707:quotient group 702: 690: 681: 675: 669: 663: 657: 651: 618: 559: 558: 546: 537: 523: 478: 466: 463:dihedral group 419: 412: 405: 400: 399: 384: 380: 374: 370: 366: 359: 355: 349: 345: 337: 333: 327: 323: 295: 292: 274: 273: 262: 259: 254: 250: 246: 243: 240: 226: 225: 214: 211: 208: 205: 200: 196: 192: 189: 186: 159:the relations 121: 120: 109: 106: 103: 100: 97: 94: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 5939: 5928: 5925: 5923: 5920: 5919: 5917: 5908: 5905: 5900: 5899: 5894: 5890: 5885: 5884: 5880: 5873: 5867: 5862: 5861: 5855: 5851: 5848: 5842: 5840:0-521-58542-2 5836: 5832: 5828: 5824: 5819: 5817:0-387-09212-9 5813: 5809: 5805: 5801: 5797: 5796: 5792: 5783: 5779: 5775: 5773:0-521-22729-1 5769: 5765: 5761: 5757: 5750: 5747: 5739: 5735: 5731: 5727: 5723: 5718: 5713: 5708: 5703: 5699: 5695: 5691: 5687: 5686: 5678: 5674: 5668: 5665: 5661: 5657: 5653: 5649: 5648: 5643: 5637: 5634: 5629: 5623: 5619: 5615: 5608: 5605: 5597: 5593: 5589: 5588: 5580: 5576: 5570: 5567: 5562: 5558: 5554: 5550: 5546: 5542: 5538: 5534: 5530: 5526: 5522: 5515: 5512: 5507: 5503: 5499: 5495: 5488: 5486: 5484: 5480: 5473: 5469: 5466: 5464: 5461: 5459: 5456: 5454: 5451: 5449: 5446: 5445: 5441: 5439: 5437: 5432: 5430: 5426: 5422: 5421: 5416: 5412: 5409:, called the 5408: 5404: 5400: 5394: 5388: 5382: 5374: 5372: 5370: 5366: 5362: 5358: 5354: 5350: 5346: 5342: 5338: 5331: 5325: 5316: 5312: 5306: 5298: 5293: 5289: 5285: 5279: 5275: 5271: 5267: 5260: 5256: 5252: 5251: 5246: 5241: 5237: 5233: 5229: 5222: 5218: 5214: 5213: 5208: 5207: 5206: 5204: 5200: 5194: 5190: 5184: 5178: 5174: 5168: 5161:Constructions 5160: 5158: 5156: 5155:William Boone 5152: 5151:Pyotr Novikov 5148: 5144: 5140: 5136: 5130: 5126: 5120: 5112: 5110: 5108: 5102: 5100: 5095: 5093: 5089: 5084: 5080: 5076: 5072: 5066: 5062: 5057: 5053: 5046: 5042: 5036: 5030:is normal in 5029: 5025: 5021: 5017: 5012: 5008: 5000: 4996: 4992: 4988: 4981: 4975: 4973: 4966:Some theorems 4965: 4963: 4962:with itself. 4961: 4940: 4928: 4924: 4915: 4911: 4892: 4882: 4879: 4875: 4871: 4866: 4858: 4855: 4846: 4841: 4833: 4830: 4827: 4824: 4821: 4815: 4810: 4802: 4799: 4796: 4790: 4785: 4777: 4774: 4768: 4763: 4759: 4755: 4750: 4746: 4742: 4739: 4736: 4733: 4723: 4721: 4718: 4717: 4714: 4695: 4692: 4688: 4682: 4678: 4674: 4671: 4666: 4662: 4658: 4655: 4652: 4649: 4639: 4637: 4633: 4629: 4625: 4624: 4621: 4604: 4601: 4598: 4595: 4592: 4589: 4586: 4583: 4580: 4577: 4574: 4571: 4566: 4563: 4559: 4553: 4550: 4546: 4542: 4539: 4536: 4533: 4530: 4527: 4524: 4521: 4518: 4515: 4505: 4503: 4500: 4499: 4496: 4492: 4488: 4484: 4480: 4476: 4472: 4453: 4449: 4445: 4440: 4436: 4432: 4429: 4426: 4423: 4413: 4411: 4410:modular group 4407: 4403: 4402: 4398: 4394: 4390: 4386: 4382: 4363: 4355: 4352: 4346: 4341: 4333: 4330: 4324: 4319: 4315: 4311: 4306: 4298: 4295: 4292: 4286: 4283: 4280: 4277: 4274: 4271: 4268: 4265: 4262: 4259: 4256: 4253: 4250: 4247: 4237: 4234: 4230: 4229: 4226: 4222: 4218: 4214: 4210: 4191: 4183: 4180: 4177: 4171: 4168: 4165: 4162: 4159: 4156: 4153: 4150: 4147: 4144: 4141: 4138: 4128: 4125: 4121: 4120: 4115: 4110: 4092: 4089: 4086: 4083: 4080: 4077: 4074: 4071: 4068: 4065: 4062: 4059: 4054: 4050: 4046: 4043: 4040: 4037: 4027: 4025: 4017: 4016: 4013: 3994: 3986: 3983: 3977: 3972: 3968: 3964: 3959: 3955: 3951: 3948: 3945: 3942: 3932: 3930: 3920: 3919: 3916: 3897: 3889: 3886: 3880: 3875: 3871: 3867: 3862: 3858: 3854: 3851: 3848: 3845: 3835: 3833: 3823: 3822: 3819: 3800: 3792: 3789: 3783: 3778: 3774: 3770: 3765: 3761: 3757: 3754: 3751: 3748: 3738: 3736: 3726: 3725: 3722: 3703: 3695: 3692: 3686: 3681: 3677: 3673: 3668: 3664: 3660: 3657: 3654: 3651: 3641: 3639: 3638:Klein 4 group 3625: 3624: 3608: 3605: 3600: 3595: 3591: 3582: 3561: 3558: 3555: 3551: 3545: 3541: 3535: 3532: 3529: 3525: 3521: 3516: 3512: 3506: 3503: 3500: 3496: 3490: 3486: 3478: 3463: 3460: 3457: 3454: 3451: 3439: 3435: 3429: 3425: 3421: 3416: 3412: 3406: 3402: 3394: 3393: 3392: 3374: 3371: 3368: 3364: 3360: 3357: 3354: 3349: 3345: 3336: 3334: 3329: 3324: 3323: 3319: 3315: 3311: 3305: 3301: 3297: 3293: 3289: 3285: 3280: 3276: 3272: 3270: 3256: 3253: 3248: 3243: 3239: 3212: 3209: 3204: 3193: 3190: 3187: 3183: 3177: 3173: 3161: 3160: 3159: 3137: 3134: 3131: 3127: 3121: 3117: 3111: 3108: 3105: 3101: 3097: 3092: 3088: 3082: 3079: 3076: 3072: 3066: 3062: 3054: 3039: 3036: 3033: 3030: 3027: 3015: 3011: 3005: 3001: 2997: 2992: 2988: 2982: 2978: 2970: 2955: 2952: 2947: 2942: 2938: 2930: 2929: 2912: 2909: 2906: 2902: 2898: 2895: 2892: 2887: 2883: 2874: 2871: 2867: 2862: 2857: 2856: 2853: 2851: 2847: 2843: 2824: 2821: 2818: 2808: 2806: 2802: 2798: 2797: 2794: 2777: 2774: 2771: 2768: 2765: 2762: 2757: 2753: 2749: 2744: 2740: 2736: 2733: 2730: 2727: 2717: 2715: 2712: 2708: 2704: 2701: 2697: 2694: 2693: 2690: 2673: 2670: 2667: 2664: 2661: 2658: 2655: 2652: 2649: 2639: 2637: 2633: 2630: 2629: 2625: 2617: 2613: 2594: 2591: 2587: 2583: 2578: 2575: 2571: 2567: 2564: 2561: 2556: 2552: 2548: 2543: 2539: 2535: 2530: 2527: 2523: 2519: 2516: 2513: 2510: 2500: 2498: 2493: 2488: 2487: 2484: 2465: 2457: 2454: 2448: 2443: 2439: 2435: 2432: 2429: 2426: 2416: 2414: 2406: 2405: 2402:a reflection 2401: 2397: 2393: 2374: 2366: 2363: 2357: 2352: 2348: 2344: 2339: 2335: 2331: 2328: 2325: 2322: 2312: 2310: 2306: 2301: 2296: 2295: 2292: 2273: 2269: 2265: 2262: 2252: 2250: 2246: 2241: 2236: 2235: 2231: 2211: 2208: 2198: 2196: 2192: 2188: 2187: 2183: 2180: 2177: 2176: 2173: 2166: 2164: 2162: 2158: 2155:, student of 2154: 2150: 2146: 2142: 2134: 2132: 2130: 2126: 2122: 2118: 2117:Graham Higman 2113: 2111: 2107: 2103: 2099: 2095: 2091: 2087: 2083: 2079: 2075: 2072: 2065: 2061: 2058:), calculate 2057: 2053: 2049: 2044: 2040: 2033: 2028: 2024: 2020: 2016: 2008: 2006: 2004: 2000: 1992: 1988: 1985:. A group is 1984: 1980: 1976: 1972: 1968: 1967: 1958: 1956: 1954: 1949: 1927: 1922: 1919: 1915: 1892: 1889: 1885: 1881: 1859: 1856: 1852: 1848: 1845: 1837: 1829: 1827: 1811: 1807: 1803: 1798: 1794: 1788: 1784: 1761: 1758: 1753: 1749: 1743: 1739: 1733: 1729: 1720: 1716: 1698: 1694: 1685: 1681: 1677: 1673: 1668: 1654: 1651: 1646: 1642: 1633: 1629: 1625: 1609: 1606: 1603: 1598: 1595: 1591: 1582: 1579:are words on 1578: 1574: 1558: 1555: 1552: 1543: 1526: 1523: 1520: 1509: 1490: 1487: 1484: 1473: 1469: 1465: 1446: 1443: 1440: 1429: 1425: 1406: 1403: 1399: 1393: 1389: 1385: 1379: 1376: 1373: 1363: 1362: 1361: 1360: 1341: 1338: 1335: 1310: 1306: 1297: 1293: 1290: 1286: 1268: 1264: 1240: 1237: 1234: 1209: 1205: 1196: 1192: 1188: 1184: 1180: 1176: 1172: 1165: 1158: 1150: 1143: 1139: 1133: 1129: 1125: 1120: 1116: 1112: 1107: 1102: 1098: 1092: 1091: 1090: 1085: 1081: 1070: 1068: 1051: 1043: 1035: 1032: 1026: 1021: 1017: 1013: 1008: 1004: 1000: 997: 994: 991: 981: 980: 979: 975: 971: 967: 946: 940: 937: 932: 924: 921: 915: 910: 906: 902: 897: 893: 889: 886: 883: 880: 870: 869: 868: 866: 860: 856: 852: 848: 841: 837: 833: 813: 807: 804: 799: 791: 788: 782: 779: 776: 771: 767: 763: 760: 757: 752: 748: 744: 741: 738: 735: 725: 724: 723: 716: 712: 708: 700: 696: 688: 684: 678: 672: 662: 656: 650: 646: 642: 638: 635: 631: 627: 622: 613: 609: 605: 601: 592: 588: 584: 580: 573: 569: 565: 551: 547: 542: 538: 533: 529: 528: 527: 521: 516: 512: 506: 502: 496: 491: 484: 476: 472: 464: 459: 457: 453: 449: 445: 441: 437: 432: 430: 426: 422: 415: 408: 382: 378: 372: 368: 364: 357: 353: 347: 343: 335: 331: 325: 321: 313: 312: 311: 309: 305: 301: 293: 291: 289: 284: 281: 279: 260: 252: 248: 244: 241: 231: 230: 229: 212: 206: 203: 198: 194: 190: 187: 177: 176: 175: 173: 169: 164: 162: 158: 154: 150: 146: 142: 138: 134: 130: 126: 107: 101: 98: 95: 85: 84: 83: 81: 77: 73: 69: 68: 63: 59: 55: 51: 47: 40: 33: 19: 5896: 5859: 5830: 5807: 5759: 5756:Wall, C.T.C. 5749: 5689: 5683: 5667: 5651: 5645: 5636: 5613: 5607: 5591: 5585: 5569: 5528: 5524: 5514: 5497: 5493: 5433: 5420:Bruhat order 5418: 5414: 5403:Cayley graph 5396: 5387:Cayley graph 5368: 5364: 5360: 5356: 5348: 5344: 5340: 5336: 5329: 5323: 5314: 5310: 5304: 5302: 5287: 5283: 5277: 5273: 5269: 5265: 5258: 5254: 5248: 5239: 5235: 5231: 5227: 5220: 5216: 5212:free product 5210: 5202: 5198: 5192: 5188: 5182: 5176: 5172: 5166: 5164: 5146: 5142: 5138: 5134: 5128: 5124: 5116: 5107:Cayley table 5104: 5098: 5097: 5091: 5087: 5082: 5078: 5074: 5070: 5060: 5055: 5048: 5044: 5040: 5031: 5027: 5019: 5015: 5010: 5003: 4990: 4983: 4979: 4977: 4971: 4970: 4920: 4631: 4627: 4494: 4490: 4486: 4482: 4479:free product 4474: 4405: 4396: 4388: 4384: 4232: 4216: 4212: 4123: 4113: 3390: 3337:generators: 3333:braid groups 3327: 3317: 3313: 3309: 3303: 3299: 3295: 3291: 3287: 3283: 3278: 3274: 3230: 3157: 2875:generators: 2869: 2860: 2849: 2841: 2804: 2713: 2710: 2706: 2702: 2699: 2695: 2635: 2631: 2623: 2491: 2399: 2395: 2308: 2299: 2248: 2245:cyclic group 2239: 2194: 2181:Presentation 2170: 2138: 2114: 2109: 2105: 2101: 2097: 2093: 2089: 2085: 2081: 2067: 2063: 2059: 2055: 2051: 2047: 2042: 2035: 2031: 2022: 2018: 2014: 2012: 2002: 1994: 1990: 1986: 1982: 1978: 1974: 1970: 1964: 1962: 1950: 1833: 1718: 1714: 1683: 1675: 1671: 1669: 1631: 1627: 1623: 1580: 1576: 1572: 1544: 1507: 1471: 1467: 1463: 1427: 1423: 1421: 1295: 1291: 1284: 1194: 1190: 1185:be a set of 1182: 1178: 1167: 1163: 1161: 1141: 1137: 1127: 1123: 1114: 1110: 1100: 1096: 1083: 1079: 1074: 1066: 973: 969: 965: 961: 864: 858: 854: 850: 846: 839: 835: 831: 828: 714: 710: 698: 694: 686: 679: 673: 667: 660: 654: 648: 644: 640: 636: 633: 629: 625: 623: 611: 607: 603: 599: 590: 586: 582: 578: 571: 567: 563: 560: 549: 540: 531: 519: 514: 510: 504: 500: 497: 489: 482: 474: 470: 460: 455: 451: 447: 443: 439: 435: 433: 428: 424: 417: 410: 403: 401: 307: 303: 297: 285: 282: 277: 275: 227: 171: 168:cyclic group 165: 160: 152: 136: 132: 128: 124: 123:Informally, 122: 79: 75: 71: 65: 61: 57: 50:presentation 49: 43: 5500:(1): 3–10. 5411:word metric 5393:Word metric 4383:nontrivial 4221:Dehn twists 3391:relations: 2928:relations: 2846:commutators 2157:Felix Klein 2129:uncountably 2112:recursive. 46:mathematics 5916:Categories 5793:References 5782:0423.20029 5734:0086.24701 5660:0068.01301 5415:weak order 5337:deficiency 5305:deficiency 5299:Deficiency 5292:commutator 5099:Corollary. 4914:commutator 4720:Tits group 2307:of order 2 2191:free group 1470:. A group 1428:generators 1175:free group 1151:Definition 576:, and let 520:not unique 402:where the 300:free group 294:Background 149:free group 141:isomorphic 67:generators 5898:MathWorld 5654:: 1–143, 5561:120100270 5553:0080-4630 5369:efficient 5157:in 1958. 5002:φ : 4993:. By the 4941:≀ 4898:⟩ 4880:− 4743:∣ 4731:⟨ 4701:⟩ 4693:− 4659:∣ 4647:⟨ 4608:⟩ 4564:− 4551:− 4531:∣ 4513:⟨ 4477:) is the 4459:⟩ 4433:∣ 4421:⟨ 4395:of SL(2, 4369:⟩ 4263:∣ 4245:⟨ 4197:⟩ 4148:∣ 4136:⟨ 4096:⟩ 4047:∣ 4035:⟨ 4000:⟩ 3952:∣ 3940:⟨ 3903:⟩ 3855:∣ 3843:⟨ 3806:⟩ 3758:∣ 3746:⟨ 3709:⟩ 3661:∣ 3649:⟨ 3592:σ 3552:σ 3542:σ 3526:σ 3513:σ 3497:σ 3487:σ 3461:± 3455:≠ 3436:σ 3426:σ 3413:σ 3403:σ 3372:− 3365:σ 3358:… 3346:σ 3240:σ 3184:σ 3174:σ 3128:σ 3118:σ 3102:σ 3089:σ 3073:σ 3063:σ 3037:± 3031:≠ 3012:σ 3002:σ 2989:σ 2979:σ 2939:σ 2910:− 2903:σ 2896:… 2884:σ 2828:⟩ 2822:∣ 2816:⟨ 2781:⟩ 2737:∣ 2725:⟨ 2677:⟩ 2659:∣ 2647:⟨ 2600:⟩ 2592:− 2576:− 2520:∣ 2508:⟨ 2471:⟩ 2436:∣ 2424:⟨ 2380:⟩ 2332:∣ 2320:⟨ 2279:⟩ 2266:∣ 2260:⟨ 2247:of order 2218:⟩ 2215:∅ 2212:∣ 2206:⟨ 2184:Comments 2121:countably 2074:recursive 1940:for some 1920:− 1890:− 1857:− 1849:∪ 1759:− 1678:from the 1607:∈ 1596:− 1530:⟩ 1524:∣ 1518:⟨ 1494:⟩ 1488:∣ 1482:⟨ 1450:⟩ 1444:∣ 1438:⟨ 1383:⟩ 1377:∣ 1371:⟨ 1345:⟩ 1339:∣ 1333:⟨ 1244:⟩ 1238:∣ 1232:⟨ 1049:⟩ 1001:∣ 989:⟨ 944:⟩ 890:∣ 878:⟨ 811:⟩ 745:∣ 733:⟨ 365:⋯ 302:on a set 258:⟩ 245:∣ 239:⟨ 210:⟩ 191:∣ 185:⟨ 170:of order 105:⟩ 99:∣ 93:⟨ 76:relations 5856:(1994). 5829:(1997). 5806:(1980). 5738:archived 5726:16590307 5675:(1958), 5596:Archived 5577:(1856). 5442:See also 5417:and the 5335:and the 5319:is just 5165:Suppose 4972:Theorem. 4960:integers 2872:symbols 2167:Examples 2034: : 1776:, where 1468:relators 1144:⟩ 1136:⟨ 1103:⟩ 1095:⟨ 1086:⟩ 1078:⟨ 1071:Notation 701:. Thus D 452:uniquely 308:uniquely 278:relators 145:quotient 5758:(ed.). 5694:Bibcode 5594:: 446. 5533:Bibcode 5077:⟩ ≅ im( 5022:be the 4912:is the 4634:), the 4473:PSL(2, 4408:), the 4404:PSL(2, 4223:on the 2135:History 1181:. Let 1173:be the 1099:| 1082:| 615:‍ 594:‍ 553:‍ 155:by the 143:to the 5868:  5849:, etc. 5837:  5814:  5780:  5770:  5732:  5724:  5717:528693 5714:  5658:  5624:  5559:  5551:  5407:metric 5333:| 5321:| 5024:kernel 4231:GL(2, 4122:SL(2, 4022:, the 3927:, the 3830:, the 3733:, the 3636:, the 3567:  3331:, the 3231:using 3216:  3143:  2864:, the 2840:where 2495:, the 2411:, the 2303:, the 2243:, the 1571:where 861:) = 1} 857:= 1, ( 842:  488:s and 5741:(PDF) 5680:(PDF) 5599:(PDF) 5582:(PDF) 5557:S2CID 5474:Notes 5290:(cf. 5197:with 4225:torus 3922:I ≅ A 3825:O ≅ S 3728:T ≅ A 3320:+2}. 3273:Here 2394:Here 2178:Group 2080:) if 1193:, so 1187:words 853:= 1, 493:' 486:' 147:of a 54:group 5866:ISBN 5835:ISBN 5812:ISBN 5768:ISBN 5722:PMID 5622:ISBN 5549:ISSN 5303:The 5247:the 5209:the 5201:and 5181:and 5145:and 5090:and 5081:) = 5047:⟩ = 4489:and 4215:and 3316:+1, 2799:the 2626:= 2 2614:The 2189:the 1717:and 1626:and 1575:and 1162:Let 666:... 604:rfrf 583:rfrf 545:, or 532:rfrf 522:in D 48:, a 5778:Zbl 5730:Zbl 5712:PMC 5702:doi 5656:Zbl 5618:374 5541:doi 5529:262 5502:doi 5367:is 5280:, ⟩ 5244:and 4989:on 4626:BS( 3631:≅ D 2868:on 2803:on 2489:Dic 2193:on 2066:of 2013:If 1977:if 1969:if 1944:in 1907:or 1713:of 1506:if 1430:of 1298:in 1294:of 1189:on 1177:on 972:, ( 849:= { 834:= { 639:of 581:= ⟨ 566:= ⟨ 555:= 1 543:= 1 534:= 1 501:rfr 495:s. 434:If 151:on 74:of 64:of 44:In 5918:: 5895:. 5891:. 5802:; 5776:. 5736:, 5728:, 5720:, 5710:, 5700:, 5690:44 5688:, 5682:, 5652:44 5620:. 5592:12 5590:. 5584:. 5555:. 5547:. 5539:. 5527:. 5523:. 5498:70 5496:. 5482:^ 5431:. 5313:| 5294:). 5276:, 5272:| 5268:, 5257:× 5238:, 5234:| 5230:, 5219:∗ 5191:| 5175:| 5137:, 5127:| 5073:| 5067:, 5043:| 5009:→ 4786:13 4630:, 4493:/3 4485:/2 4399:) 4391:– 4387:/2 4235:) 4126:) 3621:. 3312:, 3306:+1 3269:. 2705:× 2634:× 2163:. 2041:→ 2029:) 2005:. 1993:, 1955:. 1667:. 1542:. 1140:; 1126:; 1113:| 976:)} 974:rf 968:, 859:rf 838:, 637:Rx 621:. 610:, 606:, 589:, 585:, 570:, 513:= 508:, 503:= 458:. 298:A 290:. 163:. 5901:. 5874:. 5843:. 5820:. 5784:. 5704:: 5696:: 5630:. 5563:. 5543:: 5535:: 5508:. 5504:: 5365:G 5361:G 5357:G 5349:G 5345:G 5341:G 5330:R 5324:S 5317:⟩ 5315:R 5311:S 5309:⟨ 5288:T 5284:S 5278:Q 5274:R 5270:T 5266:S 5264:⟨ 5259:H 5255:G 5242:⟩ 5240:Q 5236:R 5232:T 5228:S 5226:⟨ 5221:H 5217:G 5203:T 5199:S 5195:⟩ 5193:Q 5189:T 5187:⟨ 5183:H 5179:⟩ 5177:R 5173:S 5171:⟨ 5167:G 5147:v 5143:u 5139:v 5135:u 5131:⟩ 5129:R 5125:S 5123:⟨ 5092:K 5088:G 5083:G 5079:φ 5075:K 5071:G 5069:⟨ 5061:φ 5056:K 5054:/ 5051:G 5049:F 5045:K 5041:G 5039:⟨ 5034:G 5032:F 5028:K 5020:K 5016:G 5011:G 5006:G 5004:F 4991:G 4986:G 4984:F 4980:G 4945:Z 4937:Z 4893:6 4889:) 4883:1 4876:b 4872:a 4867:4 4863:) 4859:b 4856:a 4853:( 4850:( 4847:, 4842:4 4838:] 4834:b 4831:a 4828:b 4825:, 4822:a 4819:[ 4816:, 4811:5 4807:] 4803:b 4800:, 4797:a 4794:[ 4791:, 4782:) 4778:b 4775:a 4772:( 4769:, 4764:3 4760:b 4756:, 4751:2 4747:a 4740:b 4737:, 4734:a 4696:1 4689:b 4683:m 4679:a 4675:b 4672:= 4667:n 4663:a 4656:b 4653:, 4650:a 4632:n 4628:m 4605:y 4602:z 4599:= 4596:z 4593:y 4590:, 4587:x 4584:z 4581:= 4578:z 4575:x 4572:, 4567:1 4560:y 4554:1 4547:x 4543:y 4540:x 4537:= 4534:z 4528:z 4525:, 4522:y 4519:, 4516:x 4495:Z 4491:Z 4487:Z 4483:Z 4475:Z 4454:3 4450:b 4446:, 4441:2 4437:a 4430:b 4427:, 4424:a 4406:Z 4397:Z 4389:Z 4385:Z 4364:2 4360:) 4356:b 4353:j 4350:( 4347:, 4342:2 4338:) 4334:a 4331:j 4328:( 4325:, 4320:2 4316:j 4312:, 4307:4 4303:) 4299:a 4296:b 4293:a 4290:( 4287:, 4284:b 4281:a 4278:b 4275:= 4272:a 4269:b 4266:a 4260:j 4257:, 4254:b 4251:, 4248:a 4233:Z 4217:b 4213:a 4192:4 4188:) 4184:a 4181:b 4178:a 4175:( 4172:, 4169:b 4166:a 4163:b 4160:= 4157:a 4154:b 4151:a 4145:b 4142:, 4139:a 4124:Z 4114:n 4093:j 4090:= 4087:i 4084:j 4081:i 4078:, 4075:i 4072:= 4069:j 4066:i 4063:j 4060:, 4055:4 4051:i 4044:j 4041:, 4038:i 4020:8 4018:Q 3995:5 3991:) 3987:t 3984:s 3981:( 3978:, 3973:3 3969:t 3965:, 3960:2 3956:s 3949:t 3946:, 3943:s 3924:5 3898:4 3894:) 3890:t 3887:s 3884:( 3881:, 3876:3 3872:t 3868:, 3863:2 3859:s 3852:t 3849:, 3846:s 3827:4 3801:3 3797:) 3793:t 3790:s 3787:( 3784:, 3779:3 3775:t 3771:, 3766:2 3762:s 3755:t 3752:, 3749:s 3730:4 3704:2 3700:) 3696:t 3693:s 3690:( 3687:, 3682:2 3678:t 3674:, 3669:2 3665:s 3658:t 3655:, 3652:s 3633:2 3629:4 3627:V 3609:1 3606:= 3601:2 3596:i 3562:1 3559:+ 3556:i 3546:i 3536:1 3533:+ 3530:i 3522:= 3517:i 3507:1 3504:+ 3501:i 3491:i 3476:, 3464:1 3458:i 3452:j 3440:i 3430:j 3422:= 3417:j 3407:i 3375:1 3369:n 3361:, 3355:, 3350:1 3328:n 3325:B 3318:i 3314:i 3310:i 3304:i 3300:σ 3296:i 3292:σ 3288:i 3284:i 3279:i 3275:σ 3257:1 3254:= 3249:2 3244:i 3213:1 3210:= 3205:3 3201:) 3194:1 3191:+ 3188:i 3178:i 3170:( 3138:1 3135:+ 3132:i 3122:i 3112:1 3109:+ 3106:i 3098:= 3093:i 3083:1 3080:+ 3077:i 3067:i 3052:, 3040:1 3034:i 3028:j 3016:i 3006:j 2998:= 2993:j 2983:i 2968:, 2956:1 2953:= 2948:2 2943:i 2913:1 2907:n 2899:, 2893:, 2888:1 2870:n 2861:n 2858:S 2850:S 2842:R 2825:R 2819:S 2805:S 2778:x 2775:y 2772:= 2769:y 2766:x 2763:, 2758:n 2754:y 2750:, 2745:m 2741:x 2734:y 2731:, 2728:x 2714:Z 2711:n 2709:/ 2707:Z 2703:Z 2700:m 2698:/ 2696:Z 2674:x 2671:y 2668:= 2665:y 2662:x 2656:y 2653:, 2650:x 2636:Z 2632:Z 2624:n 2620:8 2618:Q 2595:1 2588:r 2584:= 2579:1 2572:f 2568:r 2565:f 2562:, 2557:2 2553:f 2549:= 2544:n 2540:r 2536:, 2531:n 2528:2 2524:r 2517:f 2514:, 2511:r 2492:n 2466:2 2462:) 2458:f 2455:r 2452:( 2449:, 2444:2 2440:f 2433:f 2430:, 2427:r 2409:∞ 2407:D 2400:f 2396:r 2375:2 2371:) 2367:f 2364:r 2361:( 2358:, 2353:2 2349:f 2345:, 2340:n 2336:r 2329:f 2326:, 2323:r 2309:n 2300:n 2297:D 2274:n 2270:a 2263:a 2249:n 2240:n 2237:C 2209:S 2195:S 2110:R 2106:R 2094:R 2090:S 2086:U 2084:( 2082:f 2070:S 2068:F 2064:U 2060:w 2056:w 2054:( 2052:f 2048:S 2043:N 2038:S 2036:F 2032:f 2023:N 2019:I 2015:S 1979:R 1971:S 1946:S 1942:x 1928:x 1923:1 1916:x 1893:1 1886:x 1882:x 1860:1 1853:S 1846:S 1812:k 1808:g 1804:= 1799:j 1795:g 1789:i 1785:g 1762:1 1754:k 1750:g 1744:j 1740:g 1734:i 1730:g 1719:R 1715:G 1699:i 1695:g 1684:S 1676:G 1672:G 1655:1 1652:= 1647:n 1643:r 1632:r 1628:y 1624:x 1610:R 1604:x 1599:1 1592:y 1581:S 1577:y 1573:x 1559:y 1556:= 1553:x 1527:R 1521:S 1508:G 1491:R 1485:S 1472:G 1464:R 1447:R 1441:S 1424:S 1407:. 1404:N 1400:/ 1394:S 1390:F 1386:= 1380:R 1374:S 1342:R 1336:S 1311:S 1307:F 1296:R 1292:N 1285:R 1269:S 1265:F 1241:R 1235:S 1210:S 1206:F 1195:R 1191:S 1183:R 1179:S 1170:S 1168:F 1164:S 1159:. 1142:R 1138:S 1131:} 1128:R 1124:S 1122:{ 1117:) 1115:R 1111:S 1109:( 1101:R 1097:S 1084:R 1080:S 1052:. 1044:2 1040:) 1036:f 1033:r 1030:( 1027:, 1022:2 1018:f 1014:, 1009:8 1005:r 998:f 995:, 992:r 970:f 966:r 964:{ 947:. 941:1 938:= 933:2 929:) 925:f 922:r 919:( 916:= 911:2 907:f 903:= 898:8 894:r 887:f 884:, 881:r 865:R 855:f 851:r 847:R 840:f 836:r 832:S 814:. 808:1 805:= 800:2 796:) 792:f 789:r 786:( 783:, 780:1 777:= 772:2 768:f 764:, 761:1 758:= 753:8 749:r 742:f 739:, 736:r 720:8 715:N 713:/ 711:F 703:8 699:F 695:N 691:8 687:N 682:m 680:x 676:m 674:r 670:m 668:x 664:1 661:x 658:1 655:r 652:1 649:x 645:N 641:R 634:x 630:F 626:N 619:8 612:f 608:r 600:R 596:⟩ 591:f 587:r 579:R 574:⟩ 572:f 568:r 564:F 557:. 550:f 541:r 536:, 524:8 515:r 511:r 505:f 490:f 483:r 479:8 475:f 471:r 467:8 465:D 456:G 448:G 444:G 440:S 436:G 425:n 420:i 418:a 413:i 411:s 406:i 404:s 383:n 379:a 373:n 369:s 358:2 354:a 348:2 344:s 336:1 332:a 326:1 322:s 304:S 261:, 253:n 249:a 242:a 213:, 207:1 204:= 199:n 195:a 188:a 172:n 161:R 153:S 137:G 133:R 129:S 125:G 108:. 102:R 96:S 80:G 72:R 62:S 58:G 41:. 34:. 20:)

Index

Group presentation
Group representation
free presentation
mathematics
group
generators
isomorphic
quotient
free group
normal subgroup generated by
cyclic group
absolute presentation of a group
free group
dihedral group
quotient group
Relator (disambiguation)
free group
words
normal closure
quotient group
group multiplication table
equivalence classes
combinatorial group theory
finitely generated
Gödel numbering
recursive
recursively enumerable
Graham Higman
countably
Bernhard Neumann

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