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Knuth–Bendix completion algorithm

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where X is a finite set of generators and R is a set of defining relations on X. Let X be the set of all words in X (i.e. the free monoid generated by X). Since the relations R generate an equivalence relation on X*, one can consider elements of M to be the equivalence classes of X under R. For
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From the presentation of the monoid it is possible to define a rewriting system given by the relations R. If A x B is in R then either A < B in which case B → A is a rule in the rewriting system, otherwise A > B and A → B. Since < is a reduction
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If Knuth–Bendix does not succeed, it will either run forever and produce successive approximations to an infinite complete system, or fail when it encounters an unorientable equation (i.e. an equation that it cannot turn into a rewrite rule). An enhanced version will not fail on unorientable
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and weakly confluent, then the rewriting system is confluent. So, if we can add rules to the term rewriting system in order to force all critical pairs to be convergent while maintaining the strong normalizing property, then this will force the resultant rewriting system to be confluent.
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then the order < gives a consistent method for defining minimal representatives, however computing these representatives may still not be possible. In particular, if a rewriting system is used to calculate minimal representatives then the order < should also have the property:
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Although the choice of a canonical form can theoretically be made in an arbitrary fashion this approach is generally not computable. (Consider that an equivalence relation on a language can produce an infinite number of infinite classes.) If the language is
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of W. However, if the rewriting system given by the relations is converted to a confluent rewriting system via the Knuth–Bendix algorithm, then all reductions are guaranteed to produce the same irreducible word, namely the normal form for that word.
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discussed in the paper by Heyworth and Wensley listed below allows some recording or logging of the rewriting process as it proceeds. This is useful for computing identities among relations for presentations of groups.
3241: 3073: 1358:, computes a completion of the (additive) group axioms as in Knuth, Bendix (1970). It starts with the three initial equations for the group (neutral element 0, inverse elements, associativity), using 4842: 4784: 4520: 4450: 4259: 4082: 1910: 2048: 3896: 3730: 2280: 3401: 4380: 4329: 3341: 3290: 1990:
order a given word W can be reduced W > W_1 > ... > W_n where W_n is irreducible under the rewriting system. However, depending on the rules that are applied at each W
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Checking the overlaps of these rules, we find no potential failures of confluence. Therefore, we have a confluent rewriting system, and the algorithm terminates successfully.
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V. Diekert; A.J. Duncan; A.G. Myasnikov (2011). "Geodesic Rewriting Systems and Pregroups". In Oleg Bogopolski; Inna Bumagin; Olga Kharlampovich; Enric Ventura (eds.).
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is a very similar algorithm. Although developed independently, it may also be seen as the instantiation of Knuth–Bendix algorithm in the theory of
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The order of the generators may crucially affect whether the Knuth–Bendix completion terminates. As an example, consider the
818: 1386:. Critical pair computation is an instance of paramodulation for equational unit clauses. "rw" is rewriting, implementing 5405: 5374: 1864: 285: 2382:
Next, we add more reductions (that is, rewriting rules) to eliminate possible exceptions of confluence. Suppose that
1852: 40: 825:(>) on the set of all terms; it is lifted to a well-founded ordering (▻) on the set of rewrite rules by defining 5461: 5160: 1824: 1812: 47: 5205: 2071: 1872: 1836: 57: 5353: 4789: 4731: 4473: 4403: 4212: 4035: 1877: 1832: 1378:. The 10 starred equations turn out to constitute the resulting convergent rewrite system. "pm" is short for " 4885: 3251:. This is an infinite monoid but nevertheless, the Knuth–Bendix algorithm is able to solve the word problem. 2021: 5369: 5198: 3856: 3690: 2245: 2016: 773:(>) on the set of all terms, and attempts to construct a confluent and terminating term rewriting system 3364: 5338: 5263: 5219: 3138:
that might have reducible left sides (after checking if such rules have critical pairs with other rules).
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then the word problem is easily solved. A confluent rewriting system allows one to do precisely this.
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it does not finish for there are no finite convergent systems compatible with this latter order.
4548: 3806: 3640: 2926: 2288: 2145: 1379: 822: 770: 3752: 3527: 4104: 3927: 2770: 2731: 5123: 5003: 4942: 4902: 4718:{\displaystyle \langle x,y,x^{-1},y^{-1}\,|\,xy=yx,xx^{-1}=x^{-1}x=yy^{-1}=y^{-1}y=1\rangle .} 2605: 2569: 2533: 2497: 1860: 245: 2809: 2698: 5089: 5035: 4934: 4854: 1355: 61: 5024: 3613: 3575: 3423: 2899: 2872: 2671: 2644: 2470: 2443: 2412: 2385: 2355: 2328: 5410: 5292: 5111:
256–276, London Math. Soc. Lecture Note Ser., 304, Cambridge Univ. Press, Cambridge, 2003.
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Bachmair, L.; Dershowitz, N.; Hsiang, J. (Jun 1986). "Orderings for Equational Proofs".
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are string rewriting systems which can be used to give canonical labels to elements or
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finishes with a convergent system, however considering the length-lexicographic order
5440: 5390: 5093: 25: 4986:. Handbook of Theoretical Computer Science. Vol. B. Elsevier. pp. 243–320. 5176: 1966: 814: 766: 36: 5000:
Combinatorial and Geometric Group Theory: Dortmund and Ottawa-Montreal conferences
3003:, then we have an instance where confluence could fail. Hence, add the reduction 5140: 5400: 2098:
giving the rewriting system. Suppose further that we have a reduction ordering
817:, the following inference rules can be used to transform it into an equivalent 100:) is the set of all equations that can be derived by applying equations from 4897:
Jacob T. Schwartz; Domenico Cantone; Eugenio G. Omodeo; Martin Davis (2011).
5425: 5330: 5287: 5131: 4938: 1982:. An order that is both translation-invariant and a well-order is called a 28: 206:) is the set of all equations that can be confirmed by applying rules from 5075:"A Complete Proof of Correctness of the Knuth-Bendix Completion Algorithm" 5257: 5244: 4899:
Computational Logic and Set Theory: Applying Formalized Logic to Analysis
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Repeat the procedure until all overlapping left sides have been checked.
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C. Sims. 'Computations with finitely presented groups.' Cambridge, 1994.
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left-to-right to both sides until they are literally equal. Formally,
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in the class. If there is a computable method to determine for each
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it is possible to end up with two different irreducible reductions W
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The Knuth–Bendix completion with respect to lexicographic order
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similar to above, since a right-to-left application of the rule
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Bachmair, Leo; Dershowitz, Nachum; Plaisted, David A. (1989).
3236:{\displaystyle \langle x,y\mid x^{3}=y^{3}=(xy)^{3}=1\rangle } 1398:. Orienting of equations is done implicitly and not recorded. 3068:{\displaystyle \max r_{1},r_{2}\rightarrow \min r_{1},r_{2}} 2011:
Description of the algorithm for finitely presented monoids
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often requires human intuition, proving consequences from
46:. When the algorithm succeeds, it effectively solves the 683:
s deductive closure. However, there is no way to derive
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which states that if an (abstract) rewriting system is
4901:. Springer Science & Business Media. p. 200. 5002:. Springer Science & Business Media. p. 62. 4792: 4734: 4560: 4476: 4406: 4355: 4304: 4215: 4158: 4107: 4038: 3981: 3930: 3859: 3809: 3755: 3693: 3643: 3616: 3578: 3530: 3473: 3453: 3426: 3367: 3316: 3265: 3163: 3124: 3104: 3081: 3009: 2969: 2929: 2902: 2875: 2849: 2812: 2773: 2734: 2701: 2674: 2647: 2608: 2572: 2536: 2500: 2473: 2446: 2415: 2388: 2358: 2331: 2291: 2248: 2208: 2188: 2148: 2124: 2104: 2080: 2056: 2024: 1880: 1925:
it is desirable to choose a standard representative
5383: 5329: 5306: 5278: 5243: 5183: 2494:, or vice versa. In the former case, we can write 1839:. This special case is the focus of this section. 791:
Confluence (abstract rewriting)#Motivating examples
4836: 4778: 4717: 4514: 4444: 4374: 4323: 4253: 4196: 4132: 4076: 4019: 3955: 3890: 3840: 3783: 3724: 3674: 3629: 3596: 3558: 3516: 3459: 3439: 3395: 3335: 3284: 3235: 3130: 3110: 3087: 3067: 2995: 2955: 2915: 2888: 2861: 2831: 2798: 2759: 2720: 2695:, or vice versa. In the former case, we can write 2687: 2660: 2630: 2594: 2558: 2522: 2486: 2459: 2428: 2401: 2371: 2344: 2317: 2274: 2234: 2194: 2174: 2130: 2110: 2086: 2062: 2042: 1904: 605:      and       4965:Proc. IEEE Symposium on Logic in Computer Science 3039: 3010: 5227:Things a Computer Scientist Rarely Talks About 5105:Logged rewriting and identities among relators 821:(if possible): They are based on a user-given 5161: 4886:D. Knuth, "The Genesis of Attribute Grammars" 3254:Our beginning three reductions are therefore 1974:A < B → XAY < XBY for all words A,B,X,Y 1855:(or weakly confluent) if and only if all its 1354:The following example run, obtained from the 8: 5059:D. Knuth; P. Bendix (1970). J. Leech (ed.). 4709: 4561: 3230: 3164: 2668:is completely contained in (surrounded by) 2242:. Thus we begin with the set of reductions 2037: 2025: 1899: 1887: 4293:Now, we are left with the rewriting system 5168: 5154: 5146: 5109:Groups St. Andrews 2001 in Oxford. Vol. I, 5062:Simple Word Problems in Universal Algebras 4837:{\displaystyle x<y<x^{-1}<y^{-1}} 4779:{\displaystyle x<x^{-1}<y<y^{-1}} 4515:{\displaystyle y^{2}x^{2}\rightarrow xyxy} 4445:{\displaystyle yxyx\rightarrow x^{2}y^{2}} 4254:{\displaystyle y^{2}x^{2}\rightarrow xyxy} 4077:{\displaystyle yxyx\rightarrow x^{2}y^{2}} 1815:for another presentation of this example. 1482:initial("GROUP.lop", at_line_15_column_1) 1463:initial("GROUP.lop", at_line_12_column_1) 4924:"On word problems in equational theories" 4825: 4809: 4791: 4767: 4745: 4733: 4691: 4675: 4653: 4637: 4611: 4606: 4605: 4596: 4580: 4559: 4491: 4481: 4475: 4436: 4426: 4405: 4360: 4354: 4309: 4303: 4230: 4220: 4214: 4188: 4178: 4157: 4124: 4106: 4068: 4058: 4037: 4011: 4001: 3980: 3935: 3929: 3882: 3858: 3832: 3808: 3775: 3754: 3716: 3692: 3666: 3642: 3621: 3615: 3577: 3535: 3529: 3487: 3472: 3452: 3431: 3425: 3381: 3366: 3321: 3315: 3270: 3264: 3218: 3196: 3183: 3162: 3123: 3103: 3080: 3059: 3046: 3030: 3017: 3008: 2987: 2974: 2968: 2947: 2934: 2928: 2907: 2901: 2880: 2874: 2848: 2817: 2811: 2778: 2772: 2739: 2733: 2706: 2700: 2679: 2673: 2652: 2646: 2613: 2607: 2577: 2571: 2541: 2535: 2505: 2499: 2478: 2472: 2451: 2445: 2420: 2414: 2393: 2387: 2363: 2357: 2336: 2330: 2309: 2296: 2290: 2266: 2253: 2247: 2226: 2213: 2207: 2187: 2166: 2153: 2147: 2123: 2103: 2079: 2055: 2023: 1905:{\displaystyle M=\langle X\mid R\rangle } 1879: 1444:initial("GROUP.lop", at_line_9_column_1) 5426:Potrzebie system of weights and measures 1819:String rewriting systems in group theory 1400: 5359:Robinson–Schensted–Knuth correspondence 4878: 2043:{\displaystyle \langle X\mid R\rangle } 1851:states that a term rewriting system is 777:that has the same deductive closure as 761:The Knuth–Bendix algorithm takes a set 214:is again viewed as a binary relation, ( 3891:{\displaystyle xyxyx\rightarrow y^{2}} 3725:{\displaystyle yxyxy\rightarrow x^{2}} 2275:{\displaystyle P_{i}\rightarrow Q_{i}} 3396:{\displaystyle (xy)^{3}\rightarrow 1} 1932:. This representative is called the 1859:are convergent. Furthermore, we have 999:} ›         975:} ›         7: 4922:Hsiang, J.; Rusinowitch, M. (1987). 4467: 4397: 4346: 4295: 4206: 4029: 3850: 3684: 3358: 3307: 3256: 5127:"Knuth–Bendix Completion Algorithm" 5068:. Pergamon Press. pp. 263–297. 4931:Automata, Languages and Programming 5141:Knuth-Bendix Completion Visualizer 5040:10.1016/B978-0-12-046371-8.50007-9 4375:{\displaystyle y^{3}\rightarrow 1} 4324:{\displaystyle x^{3}\rightarrow 1} 3336:{\displaystyle y^{3}\rightarrow 1} 3285:{\displaystyle x^{3}\rightarrow 1} 781:. While proving consequences from 14: 5344:Knuth–Bendix completion algorithm 5103:Anne Heyworth and C.D. Wensley. " 18:Knuth–Bendix completion algorithm 789:does not. For more details, see 5192:The Art of Computer Programming 4982:(1990). Jan van Leeuwen (ed.). 4197:{\displaystyle xyxy=y^{2}x^{2}} 4020:{\displaystyle yxyx=x^{2}y^{2}} 3517:{\displaystyle (xy)^{3}=xyxyxy} 2996:{\displaystyle r_{1}\neq r_{2}} 978:⊢         544:is a "rewrite rule" version of 4607: 4497: 4419: 4366: 4315: 4236: 4051: 3915:Both of these rules obsolete ( 3875: 3709: 3484: 3474: 3387: 3378: 3368: 3327: 3276: 3215: 3205: 3036: 2259: 2235:{\displaystyle Q_{i}<P_{i}} 819:convergent term rewrite system 1: 2440:Case 1: either the prefix of 2118:among the words generated by 374:axioms, the derivation chain 286:reflexive transitive closures 5349:Knuth–Morris–Pratt algorithm 5094:10.1016/0022-0000(81)90002-7 5025:"Completion Without Failure" 4551:by the monoid presentation: 3682:, giving the reduction rule 954:        5364:Trabb Pardo–Knuth algorithm 4529: 4458: 4388: 4337: 4286: 4280: 4148: 4142: 3971: 3965: 3917: 3841:{\displaystyle xyxyx=y^{2}} 3799: 3793: 3675:{\displaystyle yxyxy=x^{2}} 3606: 3568: 2956:{\displaystyle r_{1},r_{2}} 2318:{\displaystyle P_{i}=Q_{i}} 2175:{\displaystyle P_{i}=Q_{i}} 1795: 1776: 1757: 1738: 1719: 1700: 1681: 1662: 1643: 1624: 1605: 1586: 1567: 1548: 1529: 1510: 1491: 1472: 1453: 1434: 1410: 229:) is its rewrite closure, ( 5478: 5447:Computational group theory 3784:{\displaystyle xyxyxy^{3}} 3559:{\displaystyle x^{3}yxyxy} 1843:Motivation in group theory 1825:computational group theory 1813:Word problem (mathematics) 31:for transforming a set of 5406:Knuth's up-arrow notation 5375:Knuth's Simpath algorithm 5206:Computers and Typesetting 4853:equations and produces a 4543:A non-terminating example 4133:{\displaystyle xyxyx^{3}} 3956:{\displaystyle x^{3}yxyx} 2923:first. Call the results 2799:{\displaystyle P_{i}=ABC} 2760:{\displaystyle P_{j}=ABC} 1873:finitely presented monoid 2631:{\displaystyle P_{j}=BC} 2595:{\displaystyle P_{i}=AB} 2559:{\displaystyle P_{j}=AB} 2523:{\displaystyle P_{i}=BC} 2325:can be reduced, replace 1978:This property is called 1833:finitely presented group 548:, the derivation chains 497:s deductive closure. If 104:in any order. Formally, 5199:The Complexity of Songs 4939:10.1007/3-540-18088-5_6 3848:. Hence the reduction 3524:, so consider the word 3098:After adding a rule to 2832:{\displaystyle P_{j}=B} 2721:{\displaystyle P_{i}=B} 2285:First, if any relation 2015:Suppose we are given a 24:and Peter Bendix) is a 5457:Combinatorics on words 5234:Selected papers series 4861:for the word problem. 4838: 4780: 4719: 4516: 4446: 4376: 4325: 4290:), so we remove them. 4278:These obsolete rules ( 4255: 4198: 4134: 4078: 4021: 3957: 3892: 3842: 3785: 3726: 3676: 3631: 3598: 3560: 3518: 3461: 3441: 3397: 3337: 3286: 3237: 3154:Consider the monoid: 3132: 3118:, remove any rules in 3112: 3089: 3069: 2997: 2957: 2917: 2890: 2863: 2833: 2800: 2767:; in the latter case, 2761: 2722: 2689: 2662: 2632: 2596: 2566:; in the latter case, 2560: 2524: 2488: 2461: 2430: 2403: 2373: 2346: 2319: 2276: 2236: 2196: 2176: 2142:). For each relation 2132: 2112: 2088: 2064: 2044: 1980:translation invariance 1906: 873:encompassment ordering 170:of rewrite rules, its 58:Buchberger's algorithm 5416:Quater-imaginary base 4988:Here: sect.8.1, p.293 4839: 4781: 4720: 4517: 4447: 4377: 4326: 4256: 4204:, so we add the rule 4199: 4135: 4079: 4027:, so we add the rule 4022: 3958: 3893: 3843: 3786: 3727: 3677: 3632: 3630:{\displaystyle x^{2}} 3599: 3597:{\displaystyle yxyxy} 3561: 3519: 3462: 3442: 3440:{\displaystyle x^{3}} 3398: 3338: 3287: 3238: 3150:A terminating example 3133: 3113: 3090: 3070: 2998: 2958: 2918: 2916:{\displaystyle P_{j}} 2891: 2889:{\displaystyle P_{i}} 2864: 2834: 2801: 2762: 2723: 2690: 2688:{\displaystyle P_{j}} 2663: 2661:{\displaystyle P_{i}} 2633: 2597: 2561: 2525: 2489: 2487:{\displaystyle P_{j}} 2467:equals the suffix of 2462: 2460:{\displaystyle P_{i}} 2431: 2429:{\displaystyle P_{j}} 2404: 2402:{\displaystyle P_{i}} 2379:with the reductions. 2374: 2372:{\displaystyle Q_{i}} 2347: 2345:{\displaystyle P_{i}} 2320: 2277: 2237: 2197: 2177: 2133: 2113: 2089: 2065: 2045: 1907: 1823:An important case in 813:of equations between 765:of equations between 44:term rewriting system 5370:Dijkstra's algorithm 5308:Literate programming 5213:Concrete Mathematics 5082:J. Comput. Syst. Sci 5073:Gérard Huet (1981). 5032:Rewriting Techniques 4857:system, providing a 4790: 4732: 4558: 4474: 4404: 4353: 4302: 4213: 4156: 4105: 4036: 3979: 3928: 3921:), so we remove it. 3857: 3807: 3791:and reducing using ( 3753: 3691: 3641: 3614: 3576: 3528: 3471: 3451: 3424: 3365: 3314: 3263: 3161: 3122: 3102: 3079: 3007: 2967: 2963:, respectively. If 2927: 2900: 2873: 2847: 2810: 2771: 2732: 2699: 2672: 2645: 2606: 2570: 2534: 2498: 2471: 2444: 2413: 2386: 2356: 2329: 2289: 2246: 2206: 2186: 2146: 2122: 2111:{\displaystyle <} 2102: 2078: 2054: 2022: 1878: 1865:strongly normalizing 282:relation composition 5339:Knuth's Algorithm X 4967:. pp. 346–357. 3975:). Reducing we get 3604:. Reducing using ( 3566:. Reducing using ( 2862:{\displaystyle ABC} 1849:critical pair lemma 1835:as products of the 1511:f(X,f(Y,i(f(X,Y)))) 149:equivalence closure 5396:Knuth reward check 5368:Generalization of 5124:Weisstein, Eric W. 4834: 4776: 4715: 4549:free Abelian group 4512: 4442: 4372: 4321: 4251: 4194: 4130: 4074: 4017: 3953: 3888: 3838: 3781: 3722: 3672: 3627: 3594: 3556: 3514: 3457: 3437: 3393: 3333: 3282: 3233: 3128: 3108: 3085: 3065: 2993: 2953: 2913: 2896:first, then using 2886: 2859: 2829: 2796: 2757: 2718: 2685: 2658: 2628: 2592: 2556: 2520: 2484: 2457: 2426: 2399: 2369: 2342: 2315: 2272: 2232: 2192: 2172: 2128: 2108: 2084: 2060: 2040: 1902: 823:reduction ordering 771:reduction ordering 633:demonstrate that ( 462:demonstrates that 80:of equations, its 50:for the specified 5462:Rewriting systems 5434: 5433: 5009:978-3-7643-9911-5 4948:978-3-540-18088-3 4908:978-0-85729-808-9 4537: 4536: 4466: 4465: 4396: 4395: 4345: 4344: 4276: 4275: 4099: 4098: 3913: 3912: 3749:Similarly, using 3747: 3746: 3637:. Hence, we get 3467:) is a prefix of 3460:{\displaystyle x} 3418: 3417: 3357: 3356: 3306: 3305: 3131:{\displaystyle R} 3111:{\displaystyle R} 3088:{\displaystyle R} 2195:{\displaystyle R} 2131:{\displaystyle X} 2087:{\displaystyle R} 2063:{\displaystyle X} 1853:locally confluent 1809: 1808: 1347: 1346: 887:literally similar 172:deductive closure 82:deductive closure 5469: 5170: 5163: 5156: 5147: 5137: 5136: 5097: 5079: 5069: 5067: 5051: 5050: 5048: 5046: 5029: 5020: 5014: 5013: 4995: 4989: 4987: 4975: 4969: 4968: 4960: 4954: 4952: 4928: 4919: 4913: 4912: 4894: 4888: 4883: 4866:logged rewriting 4855:ground confluent 4843: 4841: 4840: 4835: 4833: 4832: 4817: 4816: 4785: 4783: 4782: 4777: 4775: 4774: 4753: 4752: 4724: 4722: 4721: 4716: 4699: 4698: 4683: 4682: 4661: 4660: 4645: 4644: 4610: 4604: 4603: 4588: 4587: 4521: 4519: 4518: 4513: 4496: 4495: 4486: 4485: 4468: 4451: 4449: 4448: 4443: 4441: 4440: 4431: 4430: 4398: 4381: 4379: 4378: 4373: 4365: 4364: 4347: 4330: 4328: 4327: 4322: 4314: 4313: 4296: 4270: 4260: 4258: 4257: 4252: 4235: 4234: 4225: 4224: 4207: 4203: 4201: 4200: 4195: 4193: 4192: 4183: 4182: 4140:by overlapping ( 4139: 4137: 4136: 4131: 4129: 4128: 4093: 4083: 4081: 4080: 4075: 4073: 4072: 4063: 4062: 4030: 4026: 4024: 4023: 4018: 4016: 4015: 4006: 4005: 3963:by overlapping ( 3962: 3960: 3959: 3954: 3940: 3939: 3907: 3897: 3895: 3894: 3889: 3887: 3886: 3851: 3847: 3845: 3844: 3839: 3837: 3836: 3790: 3788: 3787: 3782: 3780: 3779: 3741: 3731: 3729: 3728: 3723: 3721: 3720: 3685: 3681: 3679: 3678: 3673: 3671: 3670: 3636: 3634: 3633: 3628: 3626: 3625: 3603: 3601: 3600: 3595: 3565: 3563: 3562: 3557: 3540: 3539: 3523: 3521: 3520: 3515: 3492: 3491: 3466: 3464: 3463: 3458: 3446: 3444: 3443: 3438: 3436: 3435: 3412: 3402: 3400: 3399: 3394: 3386: 3385: 3359: 3351: 3342: 3340: 3339: 3334: 3326: 3325: 3308: 3300: 3291: 3289: 3288: 3283: 3275: 3274: 3257: 3242: 3240: 3239: 3234: 3223: 3222: 3201: 3200: 3188: 3187: 3137: 3135: 3134: 3129: 3117: 3115: 3114: 3109: 3094: 3092: 3091: 3086: 3074: 3072: 3071: 3066: 3064: 3063: 3051: 3050: 3035: 3034: 3022: 3021: 3002: 3000: 2999: 2994: 2992: 2991: 2979: 2978: 2962: 2960: 2959: 2954: 2952: 2951: 2939: 2938: 2922: 2920: 2919: 2914: 2912: 2911: 2895: 2893: 2892: 2887: 2885: 2884: 2868: 2866: 2865: 2860: 2843:Reduce the word 2838: 2836: 2835: 2830: 2822: 2821: 2805: 2803: 2802: 2797: 2783: 2782: 2766: 2764: 2763: 2758: 2744: 2743: 2727: 2725: 2724: 2719: 2711: 2710: 2694: 2692: 2691: 2686: 2684: 2683: 2667: 2665: 2664: 2659: 2657: 2656: 2637: 2635: 2634: 2629: 2618: 2617: 2601: 2599: 2598: 2593: 2582: 2581: 2565: 2563: 2562: 2557: 2546: 2545: 2529: 2527: 2526: 2521: 2510: 2509: 2493: 2491: 2490: 2485: 2483: 2482: 2466: 2464: 2463: 2458: 2456: 2455: 2435: 2433: 2432: 2427: 2425: 2424: 2408: 2406: 2405: 2400: 2398: 2397: 2378: 2376: 2375: 2370: 2368: 2367: 2351: 2349: 2348: 2343: 2341: 2340: 2324: 2322: 2321: 2316: 2314: 2313: 2301: 2300: 2281: 2279: 2278: 2273: 2271: 2270: 2258: 2257: 2241: 2239: 2238: 2233: 2231: 2230: 2218: 2217: 2201: 2199: 2198: 2193: 2181: 2179: 2178: 2173: 2171: 2170: 2158: 2157: 2137: 2135: 2134: 2129: 2117: 2115: 2114: 2109: 2093: 2091: 2090: 2085: 2069: 2067: 2066: 2061: 2049: 2047: 2046: 2041: 1954:its normal form 1911: 1909: 1908: 1903: 1401: 1382:", implementing 1373: 1361: 1356:E theorem prover 1335: 1276: 1256: 1246: 1242: 1241: 1240: 1239: 1233: 1168: 1103: 1099: 1098: 1097: 1096: 1090: 1024: 1020: 1019: 1018: 1017: 1011: 903: 902: 898: 884: 880: 870: 865: 864: 863: 862: 858: 844: 758:is not allowed. 757: 726: 725: 724: 719: 716: 710: 709: 708: 703: 700: 675: 674: 673: 668: 665: 659: 658: 657: 652: 649: 629: 624: 623: 622: 617: 614: 600: 599: 598: 593: 590: 580: 579: 578: 573: 570: 543: 489: 488: 487: 482: 479: 458: 453: 452: 451: 446: 443: 433: 432: 431: 426: 423: 405: 404: 403: 398: 395: 369: 323:For example, if 319: 318: 317: 312: 309: 303: 302: 301: 296: 293: 279: 278: 277: 272: 269: 263: 262: 261: 256: 253: 243: 242: 241: 240: 234: 228: 227: 226: 225: 219: 205: 204: 203: 198: 195: 189: 188: 187: 182: 179: 165: 164: 163: 162: 156: 146: 145: 144: 139: 136: 126: 125: 124: 123: 117: 108:is considered a 99: 98: 97: 92: 89: 66:polynomial rings 5477: 5476: 5472: 5471: 5470: 5468: 5467: 5466: 5437: 5436: 5435: 5430: 5411:Man or boy test 5379: 5325: 5302: 5293:Computer Modern 5274: 5239: 5220:Surreal Numbers 5179: 5174: 5122: 5121: 5118: 5077: 5072: 5065: 5058: 5055: 5054: 5044: 5042: 5027: 5022: 5021: 5017: 5010: 4997: 4996: 4992: 4984:Rewrite Systems 4980:J.-P. Jouannaud 4978:N. Dershowitz; 4977: 4976: 4972: 4962: 4961: 4957: 4949: 4926: 4921: 4920: 4916: 4909: 4896: 4895: 4891: 4884: 4880: 4875: 4850: 4848:Generalizations 4821: 4805: 4788: 4787: 4763: 4741: 4730: 4729: 4687: 4671: 4649: 4633: 4592: 4576: 4556: 4555: 4545: 4487: 4477: 4472: 4471: 4432: 4422: 4402: 4401: 4356: 4351: 4350: 4305: 4300: 4299: 4268: 4226: 4216: 4211: 4210: 4184: 4174: 4154: 4153: 4120: 4103: 4102: 4091: 4064: 4054: 4034: 4033: 4007: 3997: 3977: 3976: 3931: 3926: 3925: 3924:Next, consider 3905: 3878: 3855: 3854: 3828: 3805: 3804: 3771: 3751: 3750: 3739: 3712: 3689: 3688: 3662: 3639: 3638: 3617: 3612: 3611: 3574: 3573: 3531: 3526: 3525: 3483: 3469: 3468: 3449: 3448: 3427: 3422: 3421: 3410: 3377: 3363: 3362: 3349: 3317: 3312: 3311: 3298: 3266: 3261: 3260: 3214: 3192: 3179: 3159: 3158: 3152: 3147: 3120: 3119: 3100: 3099: 3077: 3076: 3055: 3042: 3026: 3013: 3005: 3004: 2983: 2970: 2965: 2964: 2943: 2930: 2925: 2924: 2903: 2898: 2897: 2876: 2871: 2870: 2845: 2844: 2813: 2808: 2807: 2774: 2769: 2768: 2735: 2730: 2729: 2702: 2697: 2696: 2675: 2670: 2669: 2648: 2643: 2642: 2641:Case 2: either 2609: 2604: 2603: 2573: 2568: 2567: 2537: 2532: 2531: 2501: 2496: 2495: 2474: 2469: 2468: 2447: 2442: 2441: 2416: 2411: 2410: 2389: 2384: 2383: 2359: 2354: 2353: 2332: 2327: 2326: 2305: 2292: 2287: 2286: 2262: 2249: 2244: 2243: 2222: 2209: 2204: 2203: 2184: 2183: 2162: 2149: 2144: 2143: 2120: 2119: 2100: 2099: 2076: 2075: 2052: 2051: 2020: 2019: 2013: 2005: 2002: ≠ W' 2001: 1997: 1993: 1984:reduction order 1959: 1952: 1945: 1930: 1922: 1918: 1876: 1875: 1845: 1821: 1371: 1359: 1352: 1325: 1258: 1248: 1235: 1234: 1231: 1230: 1229: 1225: 1160: 1092: 1091: 1088: 1087: 1086: 1082: 1013: 1012: 1009: 1008: 1007: 1003: 890: 882: 878: 860: 859: 856: 855: 854: 849: 826: 807: 731: 720: 717: 714: 713: 712: 704: 701: 698: 697: 696: 679:is a member of 669: 666: 663: 662: 661: 653: 650: 647: 646: 645: 618: 615: 612: 611: 610: 594: 591: 588: 587: 586: 574: 571: 568: 567: 566: 552: 498: 493:is a member of 483: 480: 477: 476: 475: 447: 444: 441: 440: 439: 427: 424: 421: 420: 419: 399: 396: 393: 392: 391: 378: 324: 313: 310: 307: 306: 305: 297: 294: 291: 290: 289: 273: 270: 267: 266: 265: 257: 254: 251: 250: 249: 236: 235: 232: 231: 230: 221: 220: 217: 216: 215: 199: 196: 193: 192: 191: 183: 180: 177: 176: 175: 158: 157: 154: 153: 152: 140: 137: 134: 133: 132: 129:rewrite closure 119: 118: 115: 114: 113: 110:binary relation 93: 90: 87: 86: 85: 74: 12: 11: 5: 5475: 5473: 5465: 5464: 5459: 5454: 5449: 5439: 5438: 5432: 5431: 5429: 5428: 5423: 5418: 5413: 5408: 5403: 5398: 5393: 5387: 5385: 5381: 5380: 5378: 5377: 5372: 5366: 5361: 5356: 5351: 5346: 5341: 5335: 5333: 5327: 5326: 5324: 5323: 5318: 5312: 5310: 5304: 5303: 5301: 5300: 5298:Concrete Roman 5295: 5290: 5284: 5282: 5276: 5275: 5273: 5272: 5266: 5260: 5255: 5249: 5247: 5241: 5240: 5238: 5237: 5230: 5223: 5216: 5209: 5202: 5195: 5187: 5185: 5181: 5180: 5175: 5173: 5172: 5165: 5158: 5150: 5144: 5143: 5138: 5117: 5116:External links 5114: 5113: 5112: 5101: 5098: 5070: 5053: 5052: 5015: 5008: 4990: 4970: 4955: 4947: 4914: 4907: 4889: 4877: 4876: 4874: 4871: 4864:The notion of 4859:semi-algorithm 4849: 4846: 4831: 4828: 4824: 4820: 4815: 4812: 4808: 4804: 4801: 4798: 4795: 4773: 4770: 4766: 4762: 4759: 4756: 4751: 4748: 4744: 4740: 4737: 4726: 4725: 4714: 4711: 4708: 4705: 4702: 4697: 4694: 4690: 4686: 4681: 4678: 4674: 4670: 4667: 4664: 4659: 4656: 4652: 4648: 4643: 4640: 4636: 4632: 4629: 4626: 4623: 4620: 4617: 4614: 4609: 4602: 4599: 4595: 4591: 4586: 4583: 4579: 4575: 4572: 4569: 4566: 4563: 4544: 4541: 4535: 4534: 4525: 4523: 4511: 4508: 4505: 4502: 4499: 4494: 4490: 4484: 4480: 4464: 4463: 4454: 4452: 4439: 4435: 4429: 4425: 4421: 4418: 4415: 4412: 4409: 4394: 4393: 4384: 4382: 4371: 4368: 4363: 4359: 4343: 4342: 4333: 4331: 4320: 4317: 4312: 4308: 4274: 4273: 4264: 4262: 4250: 4247: 4244: 4241: 4238: 4233: 4229: 4223: 4219: 4191: 4187: 4181: 4177: 4173: 4170: 4167: 4164: 4161: 4127: 4123: 4119: 4116: 4113: 4110: 4097: 4096: 4087: 4085: 4071: 4067: 4061: 4057: 4053: 4050: 4047: 4044: 4041: 4014: 4010: 4004: 4000: 3996: 3993: 3990: 3987: 3984: 3952: 3949: 3946: 3943: 3938: 3934: 3911: 3910: 3901: 3899: 3885: 3881: 3877: 3874: 3871: 3868: 3865: 3862: 3835: 3831: 3827: 3824: 3821: 3818: 3815: 3812: 3778: 3774: 3770: 3767: 3764: 3761: 3758: 3745: 3744: 3735: 3733: 3719: 3715: 3711: 3708: 3705: 3702: 3699: 3696: 3669: 3665: 3661: 3658: 3655: 3652: 3649: 3646: 3624: 3620: 3593: 3590: 3587: 3584: 3581: 3555: 3552: 3549: 3546: 3543: 3538: 3534: 3513: 3510: 3507: 3504: 3501: 3498: 3495: 3490: 3486: 3482: 3479: 3476: 3456: 3434: 3430: 3416: 3415: 3406: 3404: 3392: 3389: 3384: 3380: 3376: 3373: 3370: 3355: 3354: 3345: 3343: 3332: 3329: 3324: 3320: 3304: 3303: 3294: 3292: 3281: 3278: 3273: 3269: 3249:shortlex order 3245: 3244: 3232: 3229: 3226: 3221: 3217: 3213: 3210: 3207: 3204: 3199: 3195: 3191: 3186: 3182: 3178: 3175: 3172: 3169: 3166: 3151: 3148: 3146: 3143: 3127: 3107: 3084: 3062: 3058: 3054: 3049: 3045: 3041: 3038: 3033: 3029: 3025: 3020: 3016: 3012: 2990: 2986: 2982: 2977: 2973: 2950: 2946: 2942: 2937: 2933: 2910: 2906: 2883: 2879: 2858: 2855: 2852: 2841: 2840: 2828: 2825: 2820: 2816: 2795: 2792: 2789: 2786: 2781: 2777: 2756: 2753: 2750: 2747: 2742: 2738: 2717: 2714: 2709: 2705: 2682: 2678: 2655: 2651: 2639: 2627: 2624: 2621: 2616: 2612: 2591: 2588: 2585: 2580: 2576: 2555: 2552: 2549: 2544: 2540: 2519: 2516: 2513: 2508: 2504: 2481: 2477: 2454: 2450: 2423: 2419: 2396: 2392: 2366: 2362: 2339: 2335: 2312: 2308: 2304: 2299: 2295: 2269: 2265: 2261: 2256: 2252: 2229: 2225: 2221: 2216: 2212: 2191: 2169: 2165: 2161: 2156: 2152: 2140:shortlex order 2127: 2107: 2083: 2059: 2039: 2036: 2033: 2030: 2027: 2012: 2009: 2003: 1999: 1995: 1994: → W 1991: 1976: 1975: 1957: 1950: 1943: 1940:for each word 1928: 1920: 1916: 1901: 1898: 1895: 1892: 1889: 1886: 1883: 1861:Newman's lemma 1857:critical pairs 1844: 1841: 1820: 1817: 1807: 1806: 1803: 1800: 1797: 1794: 1792: 1788: 1787: 1784: 1783:f(Y,i(f(X,Y))) 1781: 1778: 1775: 1773: 1769: 1768: 1765: 1764:f(Y,i(f(X,Y))) 1762: 1759: 1756: 1754: 1750: 1749: 1746: 1745:f(i(X),f(X,Y)) 1743: 1740: 1737: 1735: 1731: 1730: 1727: 1726:f(i(X),f(X,Y)) 1724: 1721: 1718: 1716: 1712: 1711: 1708: 1705: 1702: 1699: 1697: 1693: 1692: 1689: 1686: 1683: 1680: 1678: 1674: 1673: 1670: 1667: 1664: 1663:f(X,f(i(X),Y)) 1661: 1659: 1655: 1654: 1651: 1648: 1645: 1642: 1640: 1636: 1635: 1632: 1629: 1626: 1623: 1621: 1617: 1616: 1613: 1610: 1607: 1604: 1602: 1598: 1597: 1594: 1591: 1588: 1585: 1583: 1579: 1578: 1575: 1572: 1569: 1566: 1564: 1560: 1559: 1556: 1553: 1550: 1547: 1545: 1541: 1540: 1537: 1536:f(X,f(i(X),Y)) 1534: 1531: 1528: 1526: 1522: 1521: 1518: 1515: 1512: 1509: 1507: 1503: 1502: 1499: 1496: 1493: 1490: 1488: 1484: 1483: 1480: 1477: 1474: 1471: 1469: 1465: 1464: 1461: 1458: 1455: 1452: 1450: 1446: 1445: 1442: 1439: 1436: 1433: 1431: 1427: 1426: 1421: 1416: 1414: 1409: 1407: 1380:paramodulation 1351: 1348: 1345: 1344: 1322: 1315: 1300: 1297: 1290: 1284: 1278: 1277: 1222: 1215: 1200: 1197: 1182: 1176: 1170: 1169: 1157: 1142: 1136: 1133: 1126: 1111: 1105: 1104: 1079: 1072: 1057: 1054: 1047: 1032: 1026: 1025: 1000: 985: 979: 976: 961: 955: 948: 947: 940: 934: 931: 924: 909: 901: 900: 876: 806: 803: 631: 630: 460: 459: 73: 70: 60:for computing 13: 10: 9: 6: 4: 3: 2: 5474: 5463: 5460: 5458: 5455: 5453: 5450: 5448: 5445: 5444: 5442: 5427: 5424: 5422: 5419: 5417: 5414: 5412: 5409: 5407: 5404: 5402: 5399: 5397: 5394: 5392: 5391:Dancing Links 5389: 5388: 5386: 5382: 5376: 5373: 5371: 5367: 5365: 5362: 5360: 5357: 5355: 5354:Knuth shuffle 5352: 5350: 5347: 5345: 5342: 5340: 5337: 5336: 5334: 5332: 5328: 5322: 5319: 5317: 5314: 5313: 5311: 5309: 5305: 5299: 5296: 5294: 5291: 5289: 5286: 5285: 5283: 5281: 5277: 5270: 5267: 5265: 5261: 5259: 5256: 5254: 5251: 5250: 5248: 5246: 5242: 5236: 5235: 5231: 5229: 5228: 5224: 5222: 5221: 5217: 5215: 5214: 5210: 5208: 5207: 5203: 5200: 5196: 5194: 5193: 5189: 5188: 5186: 5182: 5178: 5171: 5166: 5164: 5159: 5157: 5152: 5151: 5148: 5142: 5139: 5134: 5133: 5128: 5125: 5120: 5119: 5115: 5110: 5106: 5102: 5099: 5095: 5091: 5087: 5083: 5076: 5071: 5064: 5063: 5057: 5056: 5041: 5037: 5033: 5026: 5019: 5016: 5011: 5005: 5001: 4994: 4991: 4985: 4981: 4974: 4971: 4966: 4959: 4956: 4950: 4944: 4940: 4936: 4932: 4925: 4918: 4915: 4910: 4904: 4900: 4893: 4890: 4887: 4882: 4879: 4872: 4870: 4867: 4862: 4860: 4856: 4847: 4845: 4829: 4826: 4822: 4818: 4813: 4810: 4806: 4802: 4799: 4796: 4793: 4771: 4768: 4764: 4760: 4757: 4754: 4749: 4746: 4742: 4738: 4735: 4712: 4706: 4703: 4700: 4695: 4692: 4688: 4684: 4679: 4676: 4672: 4668: 4665: 4662: 4657: 4654: 4650: 4646: 4641: 4638: 4634: 4630: 4627: 4624: 4621: 4618: 4615: 4612: 4600: 4597: 4593: 4589: 4584: 4581: 4577: 4573: 4570: 4567: 4564: 4554: 4553: 4552: 4550: 4542: 4540: 4532: 4531: 4526: 4524: 4509: 4506: 4503: 4500: 4492: 4488: 4482: 4478: 4470: 4469: 4461: 4460: 4455: 4453: 4437: 4433: 4427: 4423: 4416: 4413: 4410: 4407: 4400: 4399: 4391: 4390: 4385: 4383: 4369: 4361: 4357: 4349: 4348: 4340: 4339: 4334: 4332: 4318: 4310: 4306: 4298: 4297: 4294: 4291: 4289: 4288: 4283: 4282: 4272: 4265: 4263: 4248: 4245: 4242: 4239: 4231: 4227: 4221: 4217: 4209: 4208: 4205: 4189: 4185: 4179: 4175: 4171: 4168: 4165: 4162: 4159: 4151: 4150: 4145: 4144: 4125: 4121: 4117: 4114: 4111: 4108: 4095: 4088: 4086: 4069: 4065: 4059: 4055: 4048: 4045: 4042: 4039: 4032: 4031: 4028: 4012: 4008: 4002: 3998: 3994: 3991: 3988: 3985: 3982: 3974: 3973: 3968: 3967: 3950: 3947: 3944: 3941: 3936: 3932: 3922: 3920: 3919: 3909: 3902: 3900: 3883: 3879: 3872: 3869: 3866: 3863: 3860: 3853: 3852: 3849: 3833: 3829: 3825: 3822: 3819: 3816: 3813: 3810: 3802: 3801: 3796: 3795: 3776: 3772: 3768: 3765: 3762: 3759: 3756: 3743: 3736: 3734: 3717: 3713: 3706: 3703: 3700: 3697: 3694: 3687: 3686: 3683: 3667: 3663: 3659: 3656: 3653: 3650: 3647: 3644: 3622: 3618: 3609: 3608: 3591: 3588: 3585: 3582: 3579: 3571: 3570: 3553: 3550: 3547: 3544: 3541: 3536: 3532: 3511: 3508: 3505: 3502: 3499: 3496: 3493: 3488: 3480: 3477: 3454: 3432: 3428: 3414: 3407: 3405: 3390: 3382: 3374: 3371: 3361: 3360: 3353: 3346: 3344: 3330: 3322: 3318: 3310: 3309: 3302: 3295: 3293: 3279: 3271: 3267: 3259: 3258: 3255: 3252: 3250: 3227: 3224: 3219: 3211: 3208: 3202: 3197: 3193: 3189: 3184: 3180: 3176: 3173: 3170: 3167: 3157: 3156: 3155: 3149: 3144: 3142: 3139: 3125: 3105: 3096: 3082: 3060: 3056: 3052: 3047: 3043: 3031: 3027: 3023: 3018: 3014: 2988: 2984: 2980: 2975: 2971: 2948: 2944: 2940: 2935: 2931: 2908: 2904: 2881: 2877: 2856: 2853: 2850: 2826: 2823: 2818: 2814: 2793: 2790: 2787: 2784: 2779: 2775: 2754: 2751: 2748: 2745: 2740: 2736: 2715: 2712: 2707: 2703: 2680: 2676: 2653: 2649: 2640: 2625: 2622: 2619: 2614: 2610: 2589: 2586: 2583: 2578: 2574: 2553: 2550: 2547: 2542: 2538: 2517: 2514: 2511: 2506: 2502: 2479: 2475: 2452: 2448: 2439: 2438: 2437: 2421: 2417: 2394: 2390: 2380: 2364: 2360: 2337: 2333: 2310: 2306: 2302: 2297: 2293: 2283: 2267: 2263: 2254: 2250: 2227: 2223: 2219: 2214: 2210: 2189: 2167: 2163: 2159: 2154: 2150: 2141: 2125: 2105: 2097: 2081: 2073: 2057: 2034: 2031: 2028: 2018: 2010: 2008: 1987: 1985: 1981: 1973: 1972: 1971: 1968: 1962: 1960: 1953: 1946: 1939: 1935: 1931: 1924: 1896: 1893: 1890: 1884: 1881: 1874: 1869: 1866: 1862: 1858: 1854: 1850: 1842: 1840: 1838: 1834: 1830: 1826: 1818: 1816: 1814: 1804: 1801: 1798: 1793: 1790: 1789: 1785: 1782: 1779: 1774: 1771: 1770: 1766: 1763: 1760: 1755: 1752: 1751: 1747: 1744: 1741: 1736: 1733: 1732: 1728: 1725: 1722: 1717: 1714: 1713: 1709: 1706: 1703: 1698: 1695: 1694: 1690: 1687: 1684: 1679: 1676: 1675: 1671: 1668: 1665: 1660: 1657: 1656: 1652: 1649: 1646: 1641: 1638: 1637: 1633: 1630: 1627: 1622: 1619: 1618: 1614: 1611: 1608: 1603: 1600: 1599: 1595: 1592: 1589: 1584: 1581: 1580: 1576: 1573: 1570: 1565: 1562: 1561: 1557: 1554: 1551: 1546: 1543: 1542: 1538: 1535: 1532: 1527: 1524: 1523: 1519: 1516: 1513: 1508: 1505: 1504: 1500: 1497: 1494: 1489: 1486: 1485: 1481: 1478: 1475: 1470: 1467: 1466: 1462: 1459: 1456: 1451: 1448: 1447: 1443: 1440: 1437: 1432: 1429: 1428: 1425: 1422: 1420: 1417: 1415: 1413: 1408: 1406: 1403: 1402: 1399: 1397: 1393: 1389: 1385: 1381: 1377: 1369: 1365: 1357: 1349: 1343: 1339: 1338:critical pair 1333: 1329: 1323: 1320: 1316: 1313: 1309: 1305: 1301: 1298: 1295: 1291: 1289: 1285: 1283: 1280: 1279: 1274: 1270: 1266: 1262: 1255: 1251: 1245: 1238: 1228: 1223: 1220: 1216: 1213: 1209: 1205: 1201: 1198: 1195: 1191: 1187: 1183: 1181: 1177: 1175: 1172: 1171: 1167: 1163: 1158: 1155: 1151: 1147: 1143: 1141: 1137: 1134: 1131: 1127: 1124: 1120: 1116: 1112: 1110: 1107: 1106: 1102: 1095: 1085: 1080: 1077: 1073: 1070: 1066: 1062: 1058: 1055: 1052: 1048: 1045: 1041: 1037: 1033: 1031: 1028: 1027: 1023: 1016: 1006: 1001: 998: 994: 990: 986: 984: 980: 977: 974: 970: 966: 962: 960: 956: 953: 950: 949: 945: 941: 939: 935: 932: 929: 925: 922: 918: 914: 910: 908: 905: 904: 897: 893: 888: 877: 874: 869: 866: 852: 848: 847: 846: 842: 838: 834: 830: 824: 820: 816: 812: 804: 802: 800: 796: 792: 788: 784: 780: 776: 772: 768: 764: 759: 755: 751: 747: 743: 739: 735: 729: 723: 707: 694: 690: 686: 682: 678: 672: 656: 644: 640: 636: 628: 621: 608: 604: 597: 584: 577: 564: 560: 556: 551: 550: 549: 547: 541: 537: 533: 529: 525: 521: 517: 513: 509: 505: 501: 496: 492: 486: 473: 469: 465: 457: 450: 437: 430: 417: 413: 409: 402: 389: 385: 381: 377: 376: 375: 373: 367: 363: 359: 355: 351: 347: 343: 339: 335: 331: 327: 321: 316: 300: 287: 283: 276: 260: 247: 239: 224: 213: 209: 202: 186: 173: 169: 166:). For a set 161: 150: 143: 130: 122: 111: 107: 103: 96: 83: 79: 71: 69: 67: 63: 62:Gröbner bases 59: 55: 53: 49: 45: 42: 38: 34: 30: 27: 26:semi-decision 23: 20:(named after 19: 5452:Donald Knuth 5343: 5232: 5225: 5218: 5211: 5204: 5190: 5184:Publications 5177:Donald Knuth 5130: 5108: 5088:(1): 11–21. 5085: 5081: 5061: 5043:. Retrieved 5031: 5018: 4999: 4993: 4983: 4973: 4964: 4958: 4930: 4917: 4898: 4892: 4881: 4863: 4851: 4727: 4546: 4538: 4528: 4457: 4387: 4336: 4292: 4285: 4279: 4277: 4266: 4147: 4141: 4101:Considering 4100: 4089: 3970: 3964: 3923: 3916: 3914: 3903: 3798: 3792: 3748: 3737: 3605: 3567: 3420:A suffix of 3419: 3408: 3347: 3296: 3253: 3246: 3153: 3140: 3097: 2842: 2381: 2284: 2094:is a set of 2070:is a set of 2017:presentation 2014: 1988: 1983: 1979: 1977: 1967:well-ordered 1963: 1955: 1948: 1941: 1937: 1933: 1926: 1914: 1870: 1846: 1822: 1810: 1796:f(i(X),i(Y)) 1593:f(X,i(i(Y))) 1574:f(0,i(i(X))) 1555:f(0,i(i(X))) 1423: 1418: 1411: 1404: 1395: 1391: 1387: 1383: 1375: 1367: 1363: 1353: 1341: 1331: 1327: 1318: 1311: 1307: 1303: 1293: 1287: 1281: 1272: 1268: 1264: 1260: 1253: 1249: 1243: 1236: 1226: 1218: 1211: 1207: 1203: 1193: 1189: 1185: 1179: 1173: 1165: 1161: 1153: 1149: 1145: 1139: 1129: 1122: 1118: 1114: 1108: 1100: 1093: 1083: 1075: 1068: 1064: 1060: 1050: 1043: 1039: 1035: 1029: 1021: 1014: 1004: 996: 992: 988: 982: 972: 968: 964: 958: 951: 943: 937: 927: 920: 916: 912: 906: 895: 891: 867: 850: 840: 836: 832: 828: 810: 809:Given a set 808: 798: 794: 786: 782: 778: 774: 762: 760: 753: 749: 745: 741: 737: 733: 727: 721: 705: 692: 688: 684: 680: 676: 670: 654: 642: 638: 634: 632: 626: 619: 606: 602: 595: 582: 575: 562: 558: 554: 545: 539: 535: 531: 527: 523: 519: 515: 511: 507: 503: 499: 494: 490: 484: 471: 467: 463: 461: 455: 448: 435: 428: 415: 411: 407: 400: 387: 383: 379: 365: 361: 357: 353: 349: 345: 341: 337: 333: 329: 325: 322: 314: 298: 274: 258: 237: 222: 211: 207: 200: 184: 171: 167: 159: 141: 120: 105: 101: 94: 81: 77: 75: 72:Introduction 56: 48:word problem 22:Donald Knuth 17: 15: 5401:Knuth Prize 5045:24 December 3247:We use the 1938:normal form 1913:each class 1871:Consider a 1805:pm(83,151) 1498:f(X,f(0,Y)) 1479:f(X,f(Y,Z)) 1473:f(f(X,Y),Z) 1156:}  › 5441:Categories 5331:Algorithms 4873:References 4152:), we get 3803:), we get 3610:), we get 3572:), we get 2202:, suppose 2072:generators 1837:generators 1786:rw(134,1) 1748:rw(79,52) 1691:rw(63,52) 1653:pm(46,52) 1615:rw(36,46) 797:and using 581:  1⋅ 76:For a set 5288:AMS Euler 5132:MathWorld 4827:− 4811:− 4769:− 4747:− 4710:⟩ 4693:− 4677:− 4655:− 4639:− 4598:− 4582:− 4562:⟨ 4498:→ 4420:→ 4367:→ 4316:→ 4237:→ 4052:→ 3876:→ 3710:→ 3388:→ 3328:→ 3277:→ 3231:⟩ 3177:∣ 3165:⟨ 3037:→ 2981:≠ 2436:overlap. 2260:→ 2096:relations 2038:⟩ 2032:∣ 2026:⟨ 1934:canonical 1900:⟩ 1894:∣ 1888:⟨ 1811:See also 1802:i(f(Y,X)) 1767:pm(83,6) 1758:f(i(X),0) 1729:pm(3,74) 1710:pm(2,67) 1701:f(i(X),X) 1672:rw(7,52) 1634:pm(2,52) 1596:pm(5,36) 1577:rw(27,1) 1454:f(X,i(X)) 1196:} › 434:  1⋅ 390:)   284:of their 280:) is the 244:) is its 147:) is the 127:) is its 41:confluent 39:) into a 33:equations 29:algorithm 5258:Metafont 5245:Software 5034:: 1–30. 3447:(namely 3145:Examples 2050:, where 1558:pm(7,2) 1539:pm(3,2) 1520:pm(2,3) 1501:pm(3,1) 1396:simplify 1392:collapse 1321: › 1296: › 1221: › 1174:Collapse 1132: › 1078: › 1053: › 1030:Simplify 946: › 930: › 769:, and a 406:  ( 370:are the 246:converse 5421:-yllion 5262:MIXAL ( 4953:, p. 55 4284:) and ( 4146:) and ( 3969:) and ( 3797:) and ( 2138:(e.g., 1923:, ... } 1682:i(i(X)) 1644:i(i(X)) 1388:compose 1350:Example 1302:‹  1286:‹  1202:‹  1178:‹  1138:‹  1113:‹  1059:‹  1034:‹  981:‹  957:‹  952:Compose 936:‹  911:‹  871:in the 625:  609:  601:  585:  565:  454:  438:  418:  248:, and ( 131:, and ( 52:algebra 5006:  4945:  4905:  2869:using 1829:cosets 1720:f(0,Y) 1650:f(0,X) 1606:f(0,X) 1587:f(X,Y) 1549:f(X,0) 1530:f(0,Y) 1492:f(X,Y) 1435:f(X,0) 1424:Source 1394:, and 1384:deduce 1370:, and 1360:f(X,Y) 1282:Deduce 1109:Orient 907:Delete 518:→ 1, ( 502:= { 1⋅ 344:= 1, ( 35:(over 5384:Other 5280:Fonts 5078:(PDF) 5066:(PDF) 5028:(PDF) 4927:(PDF) 1831:of a 1374:for − 1336:is a 1267:) ▻ ( 1257:with 1164:> 894:> 835:) ▻ ( 815:terms 805:Rules 767:terms 372:group 328:= {1⋅ 37:terms 5321:CWEB 5269:MMIX 5107:." 5047:2021 5004:ISBN 4943:ISBN 4903:ISBN 4819:< 4803:< 4797:< 4761:< 4755:< 4739:< 2806:and 2728:and 2602:and 2530:and 2409:and 2352:and 2220:< 2106:< 2074:and 1847:The 1791:165: 1777:i(X) 1772:151: 1753:134: 1625:i(0) 1372:i(X) 1362:for 889:and 885:are 881:and 875:, or 857:> 845:if 304:and 151:of ( 16:The 5316:WEB 5264:MIX 5253:TeX 5090:doi 5036:doi 4935:doi 3075:to 3040:min 3011:max 2182:in 1996:i+1 1936:or 1919:, w 1734:83: 1715:79: 1696:74: 1677:67: 1658:64: 1639:63: 1620:60: 1601:52: 1582:46: 1563:36: 1544:27: 1419:Rhs 1412:Lhs 1340:of 1324:if 1247:by 1224:if 1159:if 1081:if 1002:if 542:) } 474:) 320:). 112:, ( 5443:: 5129:. 5086:23 5084:. 5080:. 5030:. 4941:. 4929:. 3095:. 2282:. 1986:. 1915:{w 1525:7: 1506:6: 1487:5: 1468:3: 1449:2: 1430:1: 1405:Nr 1390:, 1317:, 1314:} 1310:= 1306:∪{ 1299:⊢ 1292:, 1271:→ 1263:→ 1252:→ 1217:, 1214:} 1210:= 1206:∪{ 1199:⊢ 1192:→ 1188:∪{ 1184:, 1152:→ 1148:∪{ 1144:, 1135:⊢ 1128:, 1125:} 1121:= 1117:∪{ 1074:, 1071:} 1067:= 1063:∪{ 1056:⊢ 1049:, 1046:} 1042:= 1038:∪{ 995:→ 991:∪{ 987:, 971:→ 967:∪{ 963:, 942:, 933:⊢ 926:, 923:} 919:= 915:∪{ 839:→ 831:→ 801:. 748:⋅( 744:→ 740:)⋅ 695:) 687:⋅( 681:R' 641:)⋅ 561:)⋅ 534:⋅( 530:→ 526:)⋅ 510:, 506:→ 495:E' 466:⋅( 414:)⋅ 382:⋅( 368:)} 360:⋅( 356:= 352:)⋅ 336:, 332:= 264:∘ 190:∘ 68:. 54:. 5271:) 5201:" 5197:" 5169:e 5162:t 5155:v 5135:. 5096:. 5092:: 5049:. 5038:: 5012:. 4951:. 4937:: 4911:. 4830:1 4823:y 4814:1 4807:x 4800:y 4794:x 4772:1 4765:y 4758:y 4750:1 4743:x 4736:x 4713:. 4707:1 4704:= 4701:y 4696:1 4689:y 4685:= 4680:1 4673:y 4669:y 4666:= 4663:x 4658:1 4651:x 4647:= 4642:1 4635:x 4631:x 4628:, 4625:x 4622:y 4619:= 4616:y 4613:x 4608:| 4601:1 4594:y 4590:, 4585:1 4578:x 4574:, 4571:y 4568:, 4565:x 4533:) 4530:7 4527:( 4522:. 4510:y 4507:x 4504:y 4501:x 4493:2 4489:x 4483:2 4479:y 4462:) 4459:6 4456:( 4438:2 4434:y 4428:2 4424:x 4417:x 4414:y 4411:x 4408:y 4392:) 4389:2 4386:( 4370:1 4362:3 4358:y 4341:) 4338:1 4335:( 4319:1 4311:3 4307:x 4287:5 4281:4 4271:) 4269:7 4267:( 4261:. 4249:y 4246:x 4243:y 4240:x 4232:2 4228:x 4222:2 4218:y 4190:2 4186:x 4180:2 4176:y 4172:= 4169:y 4166:x 4163:y 4160:x 4149:5 4143:1 4126:3 4122:x 4118:y 4115:x 4112:y 4109:x 4094:) 4092:6 4090:( 4084:. 4070:2 4066:y 4060:2 4056:x 4049:x 4046:y 4043:x 4040:y 4013:2 4009:y 4003:2 3999:x 3995:= 3992:x 3989:y 3986:x 3983:y 3972:5 3966:1 3951:x 3948:y 3945:x 3942:y 3937:3 3933:x 3918:3 3908:) 3906:5 3904:( 3898:. 3884:2 3880:y 3873:x 3870:y 3867:x 3864:y 3861:x 3834:2 3830:y 3826:= 3823:x 3820:y 3817:x 3814:y 3811:x 3800:3 3794:2 3777:3 3773:y 3769:x 3766:y 3763:x 3760:y 3757:x 3742:) 3740:4 3738:( 3732:. 3718:2 3714:x 3707:y 3704:x 3701:y 3698:x 3695:y 3668:2 3664:x 3660:= 3657:y 3654:x 3651:y 3648:x 3645:y 3623:2 3619:x 3607:3 3592:y 3589:x 3586:y 3583:x 3580:y 3569:1 3554:y 3551:x 3548:y 3545:x 3542:y 3537:3 3533:x 3512:y 3509:x 3506:y 3503:x 3500:y 3497:x 3494:= 3489:3 3485:) 3481:y 3478:x 3475:( 3455:x 3433:3 3429:x 3413:) 3411:3 3409:( 3403:. 3391:1 3383:3 3379:) 3375:y 3372:x 3369:( 3352:) 3350:2 3348:( 3331:1 3323:3 3319:y 3301:) 3299:1 3297:( 3280:1 3272:3 3268:x 3243:. 3228:1 3225:= 3220:3 3216:) 3212:y 3209:x 3206:( 3203:= 3198:3 3194:y 3190:= 3185:3 3181:x 3174:y 3171:, 3168:x 3126:R 3106:R 3083:R 3061:2 3057:r 3053:, 3048:1 3044:r 3032:2 3028:r 3024:, 3019:1 3015:r 2989:2 2985:r 2976:1 2972:r 2949:2 2945:r 2941:, 2936:1 2932:r 2909:j 2905:P 2882:i 2878:P 2857:C 2854:B 2851:A 2839:. 2827:B 2824:= 2819:j 2815:P 2794:C 2791:B 2788:A 2785:= 2780:i 2776:P 2755:C 2752:B 2749:A 2746:= 2741:j 2737:P 2716:B 2713:= 2708:i 2704:P 2681:j 2677:P 2654:i 2650:P 2638:. 2626:C 2623:B 2620:= 2615:j 2611:P 2590:B 2587:A 2584:= 2579:i 2575:P 2554:B 2551:A 2548:= 2543:j 2539:P 2518:C 2515:B 2512:= 2507:i 2503:P 2480:j 2476:P 2453:i 2449:P 2422:j 2418:P 2395:i 2391:P 2365:i 2361:Q 2338:i 2334:P 2311:i 2307:Q 2303:= 2298:i 2294:P 2268:i 2264:Q 2255:i 2251:P 2228:i 2224:P 2215:i 2211:Q 2190:R 2168:i 2164:Q 2160:= 2155:i 2151:P 2126:X 2082:R 2058:X 2035:R 2029:X 2004:m 2000:n 1992:i 1958:i 1956:w 1951:k 1949:w 1944:k 1942:w 1929:k 1927:w 1921:2 1917:1 1897:R 1891:X 1885:= 1882:M 1799:= 1780:= 1761:= 1742:= 1739:Y 1723:= 1707:0 1704:= 1688:X 1685:= 1669:Y 1666:= 1647:= 1631:0 1628:= 1612:X 1609:= 1590:= 1571:= 1568:X 1552:= 1533:= 1517:0 1514:= 1495:= 1476:= 1460:0 1457:= 1441:X 1438:= 1376:X 1368:Y 1366:+ 1364:X 1342:R 1334:) 1332:t 1330:, 1328:s 1326:( 1319:R 1312:t 1308:s 1304:E 1294:R 1288:E 1275:) 1273:r 1269:l 1265:t 1261:s 1259:( 1254:r 1250:l 1244:u 1237:R 1232:⟶ 1227:s 1219:R 1212:t 1208:u 1204:E 1194:t 1190:s 1186:R 1180:E 1166:t 1162:s 1154:t 1150:s 1146:R 1140:E 1130:R 1123:t 1119:s 1115:E 1101:u 1094:R 1089:⟶ 1084:t 1076:R 1069:u 1065:s 1061:E 1051:R 1044:t 1040:s 1036:E 1022:u 1015:R 1010:⟶ 1005:t 997:u 993:s 989:R 983:E 973:t 969:s 965:R 959:E 944:R 938:E 928:R 921:s 917:s 913:E 899:. 896:r 892:t 883:l 879:s 868:l 861:e 851:s 843:) 841:r 837:l 833:t 829:s 827:( 811:E 799:R 795:E 787:R 783:E 779:E 775:R 763:E 756:) 754:z 752:⋅ 750:y 746:x 742:z 738:y 736:⋅ 734:x 732:( 728:b 722:R 718:⟵ 715:⁎ 711:∘ 706:R 702:⟶ 699:⁎ 693:b 691:⋅ 689:a 685:a 677:b 671:R 667:⟵ 664:⁎ 660:∘ 655:R 651:⟶ 648:⁎ 643:b 639:a 637:⋅ 635:a 627:b 620:R 616:⟵ 613:⁎ 607:b 603:b 596:R 592:⟶ 589:⁎ 583:b 576:R 572:⟶ 569:⁎ 563:b 559:a 557:⋅ 555:a 553:( 546:E 540:z 538:⋅ 536:y 532:x 528:z 524:y 522:⋅ 520:x 516:x 514:⋅ 512:x 508:x 504:x 500:R 491:b 485:E 481:⟷ 478:⁎ 472:b 470:⋅ 468:a 464:a 456:b 449:E 445:⟷ 442:⁎ 436:b 429:E 425:⟷ 422:⁎ 416:b 412:a 410:⋅ 408:a 401:E 397:⟷ 394:⁎ 388:b 386:⋅ 384:a 380:a 366:z 364:⋅ 362:y 358:x 354:z 350:y 348:⋅ 346:x 342:x 340:⋅ 338:x 334:x 330:x 326:E 315:R 311:⟵ 308:⁎ 299:R 295:⟶ 292:⁎ 288:( 275:R 271:⟵ 268:⁎ 259:R 255:⟶ 252:⁎ 238:R 233:⟵ 223:R 218:⟶ 212:R 208:R 201:R 197:⟵ 194:⁎ 185:R 181:⟶ 178:⁎ 174:( 168:R 160:E 155:⟶ 142:E 138:⟷ 135:⁎ 121:E 116:⟶ 106:E 102:E 95:E 91:⟷ 88:⁎ 84:( 78:E

Index

Donald Knuth
semi-decision
algorithm
equations
terms
confluent
term rewriting system
word problem
algebra
Buchberger's algorithm
Gröbner bases
polynomial rings
binary relation
rewrite closure
equivalence closure
converse
relation composition
reflexive transitive closures
group
terms
reduction ordering
Confluence (abstract rewriting)#Motivating examples
terms
convergent term rewrite system
reduction ordering
>e
encompassment ordering
literally similar
critical pair
E theorem prover

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