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Formal grammar

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3474: 3133: 28: 7358: 3469:{\displaystyle {\begin{aligned}{\boldsymbol {S}}&{\underset {1}{\Rightarrow }}{\boldsymbol {aBSc}}{\underset {1}{\Rightarrow }}aB{\boldsymbol {aBSc}}c\\&{\underset {2}{\Rightarrow }}aBaB{\boldsymbol {abc}}cc\\&{\underset {3}{\Rightarrow }}a{\boldsymbol {aB}}Babccc{\underset {3}{\Rightarrow }}aaB{\boldsymbol {aB}}bccc{\underset {3}{\Rightarrow }}aa{\boldsymbol {aB}}Bbccc\\&{\underset {4}{\Rightarrow }}aaaB{\boldsymbol {bb}}ccc{\underset {4}{\Rightarrow }}aaa{\boldsymbol {bb}}bccc\end{aligned}}} 3127: 4118:, the left hand side is again only a single nonterminal symbol, but now the right-hand side is also restricted. The right side may be the empty string, or a single terminal symbol, or a single terminal symbol followed by a nonterminal symbol, but nothing else. (Sometimes a broader definition is used: one can allow longer strings of terminals or single nonterminals without anything else, making languages 2963: 368:
The language generated by the grammar is defined to be the set of all strings without any nonterminal symbols that can be generated from the string consisting of a single start symbol by (possibly repeated) application of its rules in whatever way possible. If there are essentially different ways of
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formal grammar, and that the goal is to transform this generative grammar into a working parser. Strictly speaking, a generative grammar does not in any way correspond to the algorithm used to parse a language, and various algorithms have different restrictions on the form of production rules that
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Many extensions and variations on Chomsky's original hierarchy of formal grammars have been developed, both by linguists and by computer scientists, usually either in order to increase their expressive power or in order to make them easier to analyze or parse. Some forms of grammars developed
3122:{\displaystyle {\begin{aligned}{\boldsymbol {S}}&{\underset {1}{\Rightarrow }}{\boldsymbol {aBSc}}\\&{\underset {2}{\Rightarrow }}aB{\boldsymbol {abc}}c\\&{\underset {3}{\Rightarrow }}a{\boldsymbol {aB}}bcc\\&{\underset {4}{\Rightarrow }}aa{\boldsymbol {bb}}cc\end{aligned}}} 1929: 1496:. That is, each production rule maps from one string of symbols to another, where the first string (the "head") contains an arbitrary number of symbols provided at least one of them is a nonterminal. In the case that the second string (the "body") consists solely of the 4709:
An alternative approach is to formalize the language in terms of an analytic grammar in the first place, which more directly corresponds to the structure and semantics of a parser for the language. Examples of analytic grammar formalisms include the following:
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is a grammar in which the left-hand side of each production rule consists of only a single nonterminal symbol. This restriction is non-trivial; not all languages can be generated by context-free grammars. Those that can are called
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of rules for rewriting strings, along with a "start symbol" from which rewriting starts. Therefore, a grammar is usually thought of as a language generator. However, it can also sometimes be used as the basis for a
293:"—a function in computing that determines whether a given string belongs to the language or is grammatically incorrect. To describe such recognizers, formal language theory uses separate formalisms, known as 1775: 567: 3701: 2767: 1965: 4247: 4182: 3764: 3138: 2968: 3512: 2000: 1729: 305:
of symbols and analyzing each one against the grammar of the language. Most languages have the meanings of their utterances structured according to their syntax—a practice known as
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allow rewrite rules to be augmented with semantic attributes and operations, useful both for increasing grammar expressiveness and for constructing practical language translation tools.
4404: 3907: 343:). A rule can be applied to each string that contains its left-hand side and produces a string in which an occurrence of that left-hand side has been replaced with its right-hand side. 5262: 4575: 4362: 5144: 2451: 2233: 2045: 1768: 3865: 31:
An example of a formal grammar with parsed sentence. Formal grammars consist of a set of non-terminal symbols, terminal symbols, production rules, and a designated start symbol.
3585:, these two restricted types of grammars are most often used because parsers for them can be efficiently implemented. For example, all regular languages can be recognized by a 2578: 2348: 2307: 1702: 3963: 2680: 2646: 2612: 2070: 909: 430: 5737: 4548: 4518: 4488: 4458: 3994: 1632: 1192: 1161: 875: 461: 4615:, some forms of regular expression used in practice do not strictly generate the regular languages and do not show linear recognitional performance due to those deviations. 1248: 1220: 844: 4106:
is a subset of context-free languages that can be recognized in linear time. There exist various algorithms that target either this set of languages or some subset of it.
2171: 1542: 6412: 4080: 4033: 1518: 3553:. The difference between these types is that they have increasingly strict production rules and can therefore express fewer formal languages. Two important types are 1320: 1573: 4314: 3831: 2794: 1490: 742: 4609: 2910: 1466: 1041: 309:. As a result, the first step to describing the meaning of an utterance in language is to break it down part by part and look at its analyzed form (known as its 4424: 4287: 4267: 4100: 3927: 3804: 3784: 2878: 2858: 2838: 2818: 2539: 2519: 2409: 2372: 2253: 2202: 2065: 1121: 1101: 1081: 1061: 1015: 995: 975: 955: 932: 802: 782: 762: 6495: 5636: 5582: 1356: 5255: 221: 5027: 2919: 575: 3704: 6809: 914:
This grammar is not context-free due to rule 3 and it is ambiguous due to the multiple ways in which rule 2 can be used to generate sequences of
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as the leftmost symbol. An example of recursive grammar is a clause within a sentence separated by two commas. All types of grammars in the
1924:{\displaystyle x{\underset {G}{\Rightarrow }}y\iff \exists u,v,p,q\in (\Sigma \cup N)^{*}:(x=upv)\wedge (p\rightarrow q\in P)\wedge (y=uqv)} 6822: 6145: 5394: 314: 501: 5484: 5141: 4103: 6407: 6827: 6817: 6554: 5760: 5409: 6305: 5751: 3622: 2688: 6963: 4994: 4857: 297:. One of the interesting results of automata theory is that it is not possible to design a recognizer for certain formal languages. 361:; each left-hand side must contain at least one nonterminal symbol. It also distinguishes a special nonterminal symbol, called the 7060: 6804: 5629: 5577: 5562: 1938: 351: 6365: 6058: 5799: 7402: 5438: 4738: 7321: 7023: 6786: 6781: 6606: 6027: 5711: 4187: 4790: 4128: 3710: 7316: 7099: 7016: 6729: 6660: 6537: 5779: 2354:
symbols, which must be rewritten in rewrite rules, and are only interested in rewritings from the designated start symbol
331: 255: 118: 6387: 7241: 7067: 6753: 5986: 5455: 5380: 4662: 1972: 266: 88: 6392: 7392: 6724: 6463: 5721: 5622: 5552: 5151:, James Power, Department of Computer Science National University of Ireland, Maynooth Maynooth, Co. Kildare, Ireland. 239: 173: 168: 73: 7119: 7114: 3484: 214: 7048: 6638: 6032: 6000: 5691: 5448: 5225: 4734: 1978: 1707: 5765: 4046:. That is, for every context-free language, a machine can be built that takes a string as input and determines in 2456: 7382: 7338: 7287: 7184: 6682: 6643: 6120: 5373: 5112: 4714: 207: 193: 178: 42: 7179: 5794: 4367: 3870: 27: 7109: 6648: 6500: 6483: 6206: 5686: 5525: 5520: 1639: 274: 5606:
Any language in each category is generated by a grammar and by an automaton in the category in the same line.
4717:(TDPL): a highly minimalist analytic grammar formalism developed in the early 1970s to study the behavior of 1126:
That same language can alternatively be generated by a context-free, nonambiguous grammar; for instance, the
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or what can be done with them in whatever context—only their form. A formal grammar is defined as a set of
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increase the expressiveness of conventional generative grammars by allowing rewrite rules to operate on
3836: 3589:, and for useful subsets of context-free grammars there are well-known algorithms to generate efficient 3567: 350:, which is wholly defined by these rules, a grammar further distinguishes between two kinds of symbols: 163: 7357: 4775: 2548: 2315: 2262: 1657: 1500:—i.e., that it contains no symbols at all—it may be denoted with a special notation (often 3936: 2653: 2619: 2585: 882: 403: 7204: 7166: 7043: 6847: 6687: 6611: 6589: 6417: 6375: 6274: 6241: 6105: 5893: 5804: 5572: 5547: 5404: 5365: 4785: 4760: 4742: 4731:, which derives syntactic structure by examining the positional relationships between pairs of words. 4524: 4494: 4464: 4434: 3970: 3607: 3586: 3578: 3555: 2384: 1593: 1259: 1168: 1137: 851: 805: 437: 4611:
time by a finite-state machine. Although in practice, regular grammars are commonly expressed using
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is the process of recognizing an utterance (a string in natural languages) by breaking it down to a
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in particular represents the number of times production rule 1 has been applied). This grammar is
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Formal language theory, the discipline that studies formal grammars and languages, is a branch of
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first formalized generative grammars in 1956, he classified them into types now known as the
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However, the language it generates is simply the set of all nonempty strings consisting of
720: 7397: 7292: 7282: 7236: 7219: 7174: 7136: 7038: 6958: 6765: 6692: 6665: 6653: 6559: 6473: 6447: 6402: 6370: 6171: 5973: 5916: 5866: 5831: 5789: 5504: 5419: 5386: 5302: 5275: 5271: 5148: 5031: 4998: 4585: 4119: 4115: 3561: 2886: 1324: 294: 243: 183: 158: 108: 4991: 1449: 1020: 5188:, Doctoral thesis, Princeton University, Dept. of Electrical Engineering, February 1970. 3703:
defined above is not a context-free language, and this can be strictly proven using the
7277: 7256: 7214: 7194: 7089: 6944: 6542: 6532: 6517: 6451: 6325: 6201: 6090: 6085: 6063: 5664: 5515: 4670: 4409: 4272: 4252: 4085: 4039: 3912: 3789: 3769: 3582: 2863: 2843: 2823: 2803: 2524: 2504: 2394: 2357: 2238: 2187: 2050: 1106: 1086: 1066: 1046: 1000: 980: 960: 940: 917: 787: 767: 747: 148: 128: 98: 78: 5064: 1435:{\displaystyle (\Sigma \cup N)^{*}N(\Sigma \cup N)^{*}\rightarrow (\Sigma \cup N)^{*}} 7376: 7251: 6929: 6436: 6221: 6211: 6181: 6166: 5836: 5600: 5201:," Technical Report CMU-CS-91-196, Carnegie Mellon University Computer Science, 1991. 4820: 4638: 4043: 1329: 1292: 68: 4903: 7151: 6998: 6899: 6891: 6771: 6719: 6628: 6564: 6547: 6478: 6337: 6196: 5898: 5681: 5048: 4724: 3546: 1497: 1270: 470:, and can choose a rule to apply to it. If we choose rule 1, we obtain the string 2952:{\displaystyle {\boldsymbol {S}}{\underset {2}{\Rightarrow }}{\boldsymbol {abc}}} 498:, and are done. We can write this series of choices more briefly, using symbols: 7261: 7141: 6320: 6310: 6257: 5941: 5861: 5846: 5726: 5671: 5567: 5489: 5414: 5210:
Sleator, Daniel D. & Temperly, Davy, "Parsing English with a Link Grammar,"
5184: 4728: 1469: 710:{\displaystyle \{a^{n}bab^{n}\mid n\geq 0\}=\{ba,abab,aababb,aaababbb,\dotsc \}} 17: 6191: 6046: 6017: 5823: 4697:, most of these algorithms assume that the language to be parsed is initially 4632: 4289:, where the numbers may be different) is, as it can be defined by the grammar 2146:. A sentential form that contains no nonterminal symbols (i.e. is a member of 310: 290: 5165: 4895: 3565:(Type 3). The languages that can be described with such a grammar are called 7343: 7246: 6299: 6216: 6176: 6140: 6076: 5888: 5878: 5851: 3594: 3590: 1650:
The operation of a grammar can be defined in terms of relations on strings:
251: 4737:(PEGs): a more recent generalization of TDPL designed around the practical 3581:(Type 0), which can in fact express any language that can be accepted by a 4880:
Chomsky, Noam (Sep 1956). "Three models for the description of language".
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A recursive grammar is a grammar that contains production rules that are
6924: 5716: 5198: 4795: 2820:'s. Thus, the language is the set of strings that consist of 1 or more 298: 5128:
Knuth, Donald E., "Semantics of Context-Free Languages (correction),"
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that can be put through the production rules to produce a string with
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that can be derived in a finite number of steps from the start symbol
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In the classic formalization of generative grammars first proposed by
808:(only single nonterminals appear as left-hand sides) and unambiguous. 5614: 5229:, Master’s thesis, Massachusetts Institute of Technology, Sept. 2002. 4810: 247: 5226:
Packrat Parsing: a Practical Linear-Time Algorithm with Backtracking
5051:(July 1965). "On the translation of languages from left to right". 562:{\displaystyle S\Rightarrow aSb\Rightarrow aaSbb\Rightarrow aababb} 6468: 5814: 5659: 5530: 4582:
All languages generated by a regular grammar can be recognized in
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to recognize the corresponding languages those grammars generate.
1588: 26: 4971:. Reading, Mass.: Addison-Wesley Publishing Company. p. 13. 5618: 5244: 5102:, North Holland Publishing Company, Amsterdam, p. 95-109, 1971. 4941:
Algebraic and automata theoretic properties of formal languages
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Formal Languages and Computation: Models and Their Applications
3696:{\displaystyle L(G)=\left\{a^{n}b^{n}c^{n}\mid n\geq 1\right\}} 3526:", and the generated part is each time indicated in bold type.) 2762:{\displaystyle L(G)=\left\{a^{n}b^{n}c^{n}\mid n\geq 1\right\}} 1063:. This means we can generate arbitrary nonempty sequences of 369:
generating the same single string, the grammar is said to be
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Each category of languages, except those marked by a , is a
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time whether the string is a member of the language, where
1960:{\displaystyle {\overset {*}{\underset {G}{\Rightarrow }}}} 3806:'s) is context-free, as it can be defined by the grammar 2383:
For these examples, formal languages are specified using
4242:{\displaystyle \left\{a^{n}b^{m}\mid m,n\geq 1\right\}} 1731:(pronounced as "G derives in one step") on strings in 4426:
the start symbol, and the following production rules:
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the start symbol, and the following production rules:
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Some mathematical constructs regarding formal grammars
4588: 4557: 4527: 4497: 4467: 4437: 4412: 4370: 4322: 4295: 4275: 4255: 4190: 4177:{\displaystyle \left\{a^{n}b^{n}\mid n\geq 1\right\}} 4131: 4088: 4052: 4005: 3973: 3939: 3915: 3873: 3839: 3812: 3792: 3772: 3759:{\displaystyle \left\{a^{n}b^{n}\mid n\geq 1\right\}} 3713: 3625: 3487: 3136: 2966: 2922: 2889: 2866: 2846: 2826: 2806: 2775: 2691: 2656: 2622: 2588: 2551: 2527: 2507: 2459: 2417: 2397: 2360: 2318: 2265: 2241: 2210: 2190: 2152: 2073: 2053: 2014: 1981: 1941: 1778: 1737: 1710: 1660: 1596: 1555: 1530: 1506: 1478: 1452: 1359: 1308: 1230: 1202: 1171: 1140: 1109: 1089: 1069: 1049: 1023: 1003: 983: 963: 943: 920: 885: 854: 826: 790: 770: 750: 723: 578: 504: 440: 406: 5212:
Third International Workshop on Parsing Technologies
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In the following examples, the terminal symbols are
7270: 7165: 6997: 6890: 6742: 6435: 6358: 6252: 6156: 6045: 5972: 5907: 5822: 5813: 5735: 5652: 4693:Though there is a tremendous body of literature on 4122:while still defining the same class of languages.) 4603: 4569: 4542: 4512: 4482: 4452: 4418: 4398: 4356: 4308: 4281: 4261: 4241: 4176: 4094: 4074: 4027: 3988: 3957: 3921: 3901: 3859: 3825: 3798: 3778: 3758: 3695: 3506: 3468: 3121: 2951: 2904: 2872: 2852: 2832: 2812: 2788: 2761: 2674: 2640: 2606: 2572: 2533: 2513: 2493: 2445: 2403: 2366: 2342: 2301: 2247: 2227: 2196: 2165: 2138: 2059: 2039: 1994: 1959: 1923: 1762: 1723: 1696: 1626: 1567: 1536: 1512: 1484: 1460: 1434: 1314: 1242: 1214: 1186: 1155: 1115: 1095: 1075: 1055: 1035: 1009: 989: 969: 949: 926: 903: 869: 838: 796: 776: 756: 736: 709: 561: 455: 424: 3577:, respectively. Although much less powerful than 572:The language of the grammar is the infinite set 396:Suppose we have the following production rules: 4184:defined above is not regular, but the language 3507:{\displaystyle P{\underset {i}{\Rightarrow }}Q} 1043:, then rule 1 twice and rule 3 once to produce 5098:Koster , Cornelis H. A., "Affix Grammars," in 2883:Some examples of the derivation of strings in 2235:, is defined as the set of sentences built by 5630: 5256: 4875: 4873: 3999:A context-free language can be recognized in 1995:{\displaystyle {\underset {G}{\Rightarrow }}} 1724:{\displaystyle {\underset {G}{\Rightarrow }}} 474:. If we then choose rule 1 again, we replace 215: 8: 5012:Parsing Techniques – A Practical Guide 2541:consists of the following production rules: 2494:{\displaystyle \Sigma =\left\{a,b,c\right\}} 2067:; that is, a sentential form is a member of 704: 626: 620: 579: 5578:Counter-free (with aperiodic finite monoid) 5142:Notes on Formal Language Theory and Parsing 5038:, Vol. 13 No. 2, pp. 94-102, February 1970. 5025:An Efficient Context-Free Parsing Algorithm 6456: 6051: 5819: 5637: 5623: 5615: 5288: 5263: 5249: 5241: 5214:, 1993. (Revised version of above report.) 5197:Sleator, Daniel D. & Temperly, Davy, " 4727:: a form of analytic grammar designed for 4399:{\displaystyle \Sigma =\left\{a,b\right\}} 3902:{\displaystyle \Sigma =\left\{a,b\right\}} 1799: 1795: 1634:. Such a formal grammar is often called a 222: 208: 37: 4587: 4556: 4526: 4496: 4466: 4436: 4411: 4369: 4321: 4300: 4294: 4274: 4254: 4210: 4200: 4189: 4151: 4141: 4130: 4087: 4063: 4051: 4016: 4004: 3972: 3938: 3914: 3872: 3838: 3817: 3811: 3791: 3771: 3733: 3723: 3712: 3670: 3660: 3650: 3624: 3491: 3486: 3442: 3423: 3406: 3384: 3354: 3338: 3318: 3299: 3273: 3260: 3236: 3214: 3190: 3174: 3160: 3150: 3141: 3137: 3135: 3101: 3085: 3061: 3048: 3027: 3011: 2990: 2980: 2971: 2967: 2965: 2938: 2928: 2923: 2921: 2888: 2865: 2845: 2825: 2805: 2780: 2774: 2736: 2726: 2716: 2690: 2655: 2621: 2587: 2550: 2526: 2506: 2458: 2416: 2396: 2359: 2317: 2264: 2240: 2211: 2209: 2189: 2157: 2151: 2113: 2101: 2072: 2052: 2031: 2013: 1982: 1980: 1942: 1940: 1843: 1782: 1777: 1754: 1736: 1711: 1709: 1659: 1595: 1554: 1529: 1505: 1477: 1453: 1451: 1426: 1401: 1376: 1358: 1307: 1229: 1201: 1170: 1139: 1108: 1088: 1068: 1048: 1022: 1002: 982: 962: 942: 919: 884: 853: 825: 789: 769: 749: 728: 722: 602: 586: 577: 503: 439: 405: 3705:pumping lemma for context-free languages 2374:to strings without nonterminal symbols. 5172:. p. 2 – via Newspapers.com. 5001:, Context-Free Grammars, David Matuszek 4838: 3446: 3443: 3410: 3407: 3358: 3355: 3322: 3319: 3277: 3274: 3243: 3240: 3237: 3200: 3197: 3194: 3191: 3170: 3167: 3164: 3161: 3142: 3105: 3102: 3065: 3062: 3034: 3031: 3028: 3000: 2997: 2994: 2991: 2972: 2945: 2942: 2939: 2924: 2212: 258:for such strings in a formal language. 51: 5470:Linear context-free rewriting language 4969:Introduction to Formal Language Theory 4883:IRE Transactions on Information Theory 4673:if there exists a non-terminal symbol 4570:{\displaystyle B\rightarrow \epsilon } 4357:{\displaystyle N=\left\{S,A,B\right\}} 1277:consists of the following components: 977:s. This is easy to see: to generate a 486:. If we now choose rule 2, we replace 329:A grammar mainly consists of a set of 246:are valid according to the language's 5395:Linear context-free rewriting systems 5010:Grune, Dick & Jacobs, Ceriel H., 1587:A grammar is formally defined as the 1127: 1083:s and then replace each of them with 816:Suppose the rules are these instead: 7: 4104:Deterministic context-free languages 2446:{\displaystyle N=\left\{S,B\right\}} 2228:{\displaystyle {\boldsymbol {L}}(G)} 5199:Parsing English with a Link Grammar 5164:Borenstein, Seth (April 27, 2006). 5113:Semantics of Context-Free Languages 5089:, Vol. 10 No. 1, pp. 136-163, 1975. 5087:Journal of Computer Systems Science 2860:'s, followed by the same number of 2840:'s, followed by the same number of 2040:{\displaystyle (\Sigma \cup N)^{*}} 1763:{\displaystyle (\Sigma \cup N)^{*}} 5603:of the category directly above it. 5119:, Vol. 2 No. 2, pp. 127-145, 1968. 4619:Other forms of generative grammars 4371: 3874: 3860:{\displaystyle N=\left\{S\right\}} 2685:This grammar defines the language 2460: 2328: 2281: 2154: 2088: 2018: 1830: 1800: 1741: 1676: 1606: 1507: 1413: 1388: 1363: 1309: 250:. A grammar does not describe the 25: 2573:{\displaystyle S\rightarrow aBSc} 2343:{\displaystyle (N\cup \Sigma ,P)} 2302:{\displaystyle G=(N,\Sigma ,P,S)} 1697:{\displaystyle G=(N,\Sigma ,P,S)} 265:. Its applications are found in 89:Semantics (programming languages) 7356: 4863:. For more on this subject, see 4791:Extended Backus–Naur form (EBNF) 3958:{\displaystyle S\rightarrow aSb} 2675:{\displaystyle Bb\rightarrow bb} 2641:{\displaystyle Ba\rightarrow aB} 2607:{\displaystyle S\rightarrow abc} 904:{\displaystyle aSa\rightarrow b} 425:{\displaystyle S\rightarrow aSb} 313:in computer science, and as its 238:describes which strings from an 5132:, Vol. 5 No. 1, pp 95-96, 1971. 5014:, Ellis Horwood, England, 1990. 4943:. North-Holland. pp. 8–9. 4665:. For example, a grammar for a 4543:{\displaystyle B\rightarrow bB} 4513:{\displaystyle A\rightarrow bB} 4483:{\displaystyle A\rightarrow aA} 4453:{\displaystyle S\rightarrow aA} 3989:{\displaystyle S\rightarrow ab} 3786:followed by the same number of 3707:, but for example the language 1969:G derives in zero or more steps 1627:{\displaystyle (N,\Sigma ,P,S)} 1187:{\displaystyle S\rightarrow bS} 1156:{\displaystyle S\rightarrow aS} 1017:, use rule 2 twice to generate 870:{\displaystyle S\rightarrow SS} 456:{\displaystyle S\rightarrow ba} 5166:"Songbirds grasp grammar, too" 4598: 4592: 4561: 4531: 4501: 4471: 4441: 4069: 4056: 4022: 4009: 3977: 3943: 3635: 3629: 3493: 3425: 3386: 3340: 3301: 3262: 3216: 3176: 3152: 3087: 3050: 3013: 2982: 2930: 2899: 2893: 2701: 2695: 2663: 2629: 2592: 2555: 2337: 2319: 2296: 2272: 2222: 2216: 2116: 2098: 2085: 2028: 2015: 1984: 1945: 1918: 1900: 1894: 1882: 1876: 1870: 1852: 1840: 1827: 1796: 1784: 1751: 1738: 1713: 1691: 1667: 1621: 1597: 1544:) in order to avoid confusion. 1423: 1410: 1407: 1398: 1385: 1373: 1360: 1243:{\displaystyle S\rightarrow b} 1234: 1215:{\displaystyle S\rightarrow a} 1206: 1175: 1144: 895: 858: 839:{\displaystyle S\rightarrow a} 830: 538: 520: 508: 444: 410: 35:Structure of a formal language 1: 7317:History of mathematical logic 5065:10.1016/S0019-9958(65)90426-2 4102:is the length of the string. 1295:with the strings formed from 7242:Primitive recursive function 4706:are considered well-formed. 1973:reflexive transitive closure 267:theoretical computer science 5130:Mathematical Systems Theory 5117:Mathematical Systems Theory 4735:Parsing expression grammars 2166:{\displaystyle \Sigma ^{*}} 174:Programming language theory 169:Natural language processing 7419: 6306:Schröder–Bernstein theorem 6033:Monadic predicate calculus 5692:Foundations of mathematics 5485:Deterministic context-free 5410:Deterministic context-free 5185:The TMG Recognition Schema 4852:, CRC Press, p. 233, 4846:Meduna, Alexander (2014), 4653: 4042:) by an algorithm such as 3534: 1257: 384:, and the start symbol is 7352: 7339:Philosophy of mathematics 7288:Automated theorem proving 6459: 6413:Von Neumann–Bernays–Gödel 6054: 5596: 5558:Nondeterministic pushdown 5286: 5036:Communications of the ACM 4715:Top-down parsing language 2521:is the start symbol, and 1537:{\displaystyle \epsilon } 194:Automated theorem proving 179:Computational linguistics 4896:10.1109/TIT.1956.1056813 4654:Not to be confused with 4635:instead of just strings. 4075:{\displaystyle O(n^{3})} 4028:{\displaystyle O(n^{3})} 1640:phrase structure grammar 1513:{\displaystyle \Lambda } 1273:in the 1950s, a grammar 6989:Self-verifying theories 6810:Tarski's axiomatization 5761:Tarski's undefinability 5756:incompleteness theorems 5100:ALGOL 68 Implementation 5053:Information and Control 4629:Tree-adjoining grammars 4269:followed by at least 1 3522:by means of production 1549:A distinguished symbol 1347:, each rule of the form 1315:{\displaystyle \Sigma } 307:compositional semantics 271:theoretical linguistics 7403:Automata (computation) 7363:Mathematics portal 6974:Proof of impossibility 6622:propositional variable 5932:Propositional calculus 5563:Deterministic pushdown 5439:Recursively enumerable 4917:Chomsky, Noam (1957). 4776:Backus–Naur form (BNF) 4605: 4571: 4544: 4514: 4484: 4454: 4420: 4400: 4358: 4310: 4283: 4263: 4243: 4178: 4096: 4076: 4029: 3990: 3959: 3923: 3903: 3861: 3827: 3800: 3780: 3760: 3697: 3614:context-free languages 3568:context-free languages 3508: 3470: 3123: 2953: 2906: 2874: 2854: 2834: 2814: 2790: 2763: 2676: 2642: 2608: 2574: 2535: 2515: 2495: 2447: 2405: 2368: 2344: 2303: 2249: 2229: 2198: 2167: 2140: 2061: 2041: 1996: 1961: 1925: 1764: 1725: 1704:, the binary relation 1698: 1628: 1569: 1568:{\displaystyle S\in N} 1538: 1514: 1486: 1462: 1436: 1316: 1265:The syntax of grammars 1244: 1216: 1188: 1157: 1117: 1097: 1077: 1057: 1037: 1011: 991: 971: 951: 928: 905: 871: 840: 798: 778: 758: 738: 711: 563: 494:and obtain the string 482:and obtain the string 457: 426: 284:A formal grammar is a 252:meaning of the strings 154:Propositional calculus 32: 7232:Kolmogorov complexity 7185:Computably enumerable 7085:Model complete theory 6877:Principia Mathematica 5937:Propositional formula 5766:Banach–Tarski paradox 5083:Tree Adjunct Grammars 4816:Post canonical system 4667:context-free language 4606: 4572: 4545: 4515: 4485: 4455: 4421: 4401: 4359: 4311: 4309:{\displaystyle G_{3}} 4284: 4264: 4244: 4179: 4097: 4077: 4030: 3991: 3960: 3924: 3904: 3862: 3828: 3826:{\displaystyle G_{2}} 3801: 3781: 3761: 3698: 3601:Context-free grammars 3579:unrestricted grammars 3556:context-free grammars 3531:The Chomsky hierarchy 3509: 3471: 3124: 2954: 2907: 2875: 2855: 2835: 2815: 2791: 2789:{\displaystyle a^{n}} 2764: 2677: 2643: 2609: 2575: 2536: 2516: 2496: 2448: 2406: 2391:Consider the grammar 2369: 2345: 2304: 2250: 2230: 2199: 2168: 2141: 2062: 2042: 1997: 1962: 1926: 1765: 1726: 1699: 1629: 1570: 1539: 1515: 1487: 1485:{\displaystyle \cup } 1463: 1437: 1317: 1245: 1217: 1189: 1158: 1118: 1098: 1078: 1058: 1038: 1012: 992: 972: 952: 929: 906: 872: 841: 799: 779: 759: 739: 737:{\displaystyle a^{k}} 712: 564: 458: 427: 164:Mathematical notation 30: 7180:Church–Turing thesis 7167:Computability theory 6376:continuum hypothesis 5894:Square of opposition 5752:Gödel's completeness 5548:Tree stack automaton 4965:Harrison, Michael A. 4919:Syntactic Structures 4786:Concrete syntax tree 4761:Abstract syntax tree 4743:programming language 4604:{\displaystyle O(n)} 4586: 4555: 4525: 4495: 4465: 4435: 4410: 4368: 4320: 4293: 4273: 4253: 4188: 4129: 4086: 4050: 4003: 3971: 3937: 3913: 3871: 3837: 3810: 3790: 3770: 3711: 3623: 3608:context-free grammar 3587:finite-state machine 3485: 3134: 2964: 2920: 2905:{\displaystyle L(G)} 2887: 2864: 2844: 2824: 2804: 2796:denotes a string of 2773: 2689: 2654: 2620: 2586: 2549: 2525: 2505: 2457: 2415: 2395: 2385:set-builder notation 2358: 2316: 2263: 2239: 2208: 2188: 2150: 2071: 2051: 2012: 1979: 1971:) is defined as the 1939: 1776: 1735: 1708: 1658: 1594: 1553: 1528: 1504: 1476: 1450: 1357: 1306: 1260:Unrestricted grammar 1228: 1200: 1169: 1138: 1107: 1087: 1067: 1047: 1021: 1001: 981: 961: 941: 918: 883: 852: 824: 788: 768: 748: 721: 576: 502: 438: 404: 339:) with another (its 325:Introductory example 7334:Mathematical object 7225:P versus NP problem 7190:Computable function 6984:Reverse mathematics 6910:Logical consequence 6787:primitive recursive 6782:elementary function 6555:Free/bound variable 6408:Tarski–Grothendieck 5927:Logical connectives 5857:Logical equivalence 5707:Logical consequence 5456:range concatenation 5381:range concatenation 5182:Birman, Alexander, 5111:Knuth, Donald E., " 5077:Joshi, Aravind K., 4865:undecidable problem 4826:Well-formed formula 4613:regular expressions 4044:Earley's recogniser 2309:is effectively the 1642:in the literature. 1461:{\displaystyle {*}} 1288:nonterminal symbols 1130:grammar with rules 1036:{\displaystyle SSS} 466:then we start with 281:, and other areas. 263:applied mathematics 189:Formal verification 104:Well-formed formula 7393:Mathematical logic 7132:Transfer principle 7095:Semantics of logic 7080:Categorical theory 7056:Non-standard model 6570:Logical connective 5697:Information theory 5646:Mathematical logic 5147:2017-08-28 at the 5030:2020-05-19 at the 4997:2019-11-13 at the 4781:Categorial grammar 4695:parsing algorithms 4685:can be recursive. 4656:Recursive language 4650:Recursive grammars 4643:attribute grammars 4601: 4567: 4540: 4510: 4480: 4450: 4416: 4396: 4354: 4306: 4279: 4259: 4239: 4174: 4092: 4072: 4025: 3986: 3955: 3919: 3899: 3857: 3823: 3796: 3776: 3756: 3693: 3541:Generative grammar 3504: 3499: 3466: 3464: 3431: 3392: 3346: 3307: 3268: 3222: 3182: 3158: 3119: 3117: 3093: 3056: 3019: 2988: 2949: 2936: 2902: 2870: 2850: 2830: 2810: 2786: 2759: 2672: 2638: 2604: 2570: 2531: 2511: 2491: 2443: 2401: 2364: 2340: 2299: 2245: 2225: 2194: 2163: 2136: 2122: 2057: 2037: 1992: 1990: 1957: 1951: 1921: 1790: 1760: 1721: 1719: 1694: 1624: 1579:, also called the 1565: 1534: 1510: 1482: 1458: 1432: 1312: 1240: 1212: 1184: 1153: 1113: 1093: 1073: 1053: 1033: 1007: 987: 967: 947: 924: 901: 867: 836: 794: 774: 754: 734: 707: 559: 453: 422: 319:generative grammar 279:mathematical logic 114:Regular expression 33: 7370: 7369: 7302:Abstract category 7105:Theories of truth 6915:Rule of inference 6905:Natural deduction 6886: 6885: 6431: 6430: 6136:Cartesian product 6041: 6040: 5947:Many-valued logic 5922:Boolean functions 5805:Russell's paradox 5780:diagonal argument 5677:First-order logic 5612: 5611: 5591: 5590: 5553:Embedded pushdown 5449:Context-sensitive 5374:Context-sensitive 5308:Abstract machines 5293:Chomsky hierarchy 4978:978-0-201-02955-0 4950:978-0-7204-2506-2 4937:Ginsburg, Seymour 4801:Grammar framework 4771:Ambiguous grammar 4689:Analytic grammars 4683:Chomsky hierarchy 4419:{\displaystyle S} 4282:{\displaystyle b} 4262:{\displaystyle a} 4095:{\displaystyle n} 3922:{\displaystyle S} 3799:{\displaystyle b} 3779:{\displaystyle a} 3574:regular languages 3551:Chomsky hierarchy 3537:Chomsky hierarchy 3518:generates string 3492: 3424: 3385: 3339: 3300: 3261: 3215: 3175: 3151: 3086: 3049: 3012: 2981: 2929: 2873:{\displaystyle c} 2853:{\displaystyle b} 2833:{\displaystyle a} 2813:{\displaystyle a} 2534:{\displaystyle P} 2514:{\displaystyle S} 2404:{\displaystyle G} 2367:{\displaystyle S} 2248:{\displaystyle G} 2197:{\displaystyle G} 2126: 2115: 2060:{\displaystyle S} 1983: 1955: 1944: 1783: 1712: 1254:Formal definition 1116:{\displaystyle b} 1096:{\displaystyle a} 1076:{\displaystyle S} 1056:{\displaystyle b} 1010:{\displaystyle S} 990:{\displaystyle b} 970:{\displaystyle b} 950:{\displaystyle a} 927:{\displaystyle S} 797:{\displaystyle n} 777:{\displaystyle k} 757:{\displaystyle a} 232: 231: 124:Ground expression 84:Semantics (logic) 16:(Redirected from 7410: 7383:Formal languages 7361: 7360: 7312:History of logic 7307:Category of sets 7200:Decision problem 6979:Ordinal analysis 6920:Sequent calculus 6818:Boolean algebras 6758: 6757: 6732: 6703:logical/constant 6457: 6443: 6366:Zermelo–Fraenkel 6117:Set operations: 6052: 5989: 5820: 5800:Löwenheim–Skolem 5687:Formal semantics 5639: 5632: 5625: 5616: 5607: 5604: 5568:Visibly pushdown 5542:Thread automaton 5490:Visibly pushdown 5458: 5415:Visibly pushdown 5383: 5370:(no common name) 5289: 5276:formal languages 5265: 5258: 5251: 5242: 5230: 5221: 5215: 5208: 5202: 5195: 5189: 5180: 5174: 5173: 5170:Northwest Herald 5161: 5155: 5139: 5133: 5126: 5120: 5109: 5103: 5096: 5090: 5075: 5069: 5068: 5045: 5039: 5021: 5015: 5008: 5002: 4992:Sentential Forms 4989: 4983: 4982: 4961: 4955: 4954: 4933: 4927: 4926: 4914: 4908: 4907: 4877: 4868: 4862: 4843: 4766:Adaptive grammar 4719:top-down parsers 4610: 4608: 4607: 4602: 4576: 4574: 4573: 4568: 4549: 4547: 4546: 4541: 4519: 4517: 4516: 4511: 4489: 4487: 4486: 4481: 4459: 4457: 4456: 4451: 4425: 4423: 4422: 4417: 4405: 4403: 4402: 4397: 4395: 4391: 4363: 4361: 4360: 4355: 4353: 4349: 4315: 4313: 4312: 4307: 4305: 4304: 4288: 4286: 4285: 4280: 4268: 4266: 4265: 4260: 4248: 4246: 4245: 4240: 4238: 4234: 4215: 4214: 4205: 4204: 4183: 4181: 4180: 4175: 4173: 4169: 4156: 4155: 4146: 4145: 4120:easier to denote 4116:regular grammars 4110:Regular grammars 4101: 4099: 4098: 4093: 4081: 4079: 4078: 4073: 4068: 4067: 4034: 4032: 4031: 4026: 4021: 4020: 3995: 3993: 3992: 3987: 3964: 3962: 3961: 3956: 3928: 3926: 3925: 3920: 3908: 3906: 3905: 3900: 3898: 3894: 3866: 3864: 3863: 3858: 3856: 3832: 3830: 3829: 3824: 3822: 3821: 3805: 3803: 3802: 3797: 3785: 3783: 3782: 3777: 3765: 3763: 3762: 3757: 3755: 3751: 3738: 3737: 3728: 3727: 3702: 3700: 3699: 3694: 3692: 3688: 3675: 3674: 3665: 3664: 3655: 3654: 3562:regular grammars 3525: 3521: 3517: 3513: 3511: 3510: 3505: 3500: 3475: 3473: 3472: 3467: 3465: 3449: 3432: 3413: 3393: 3380: 3361: 3347: 3325: 3308: 3280: 3269: 3256: 3246: 3223: 3210: 3203: 3183: 3173: 3159: 3145: 3128: 3126: 3125: 3120: 3118: 3108: 3094: 3081: 3068: 3057: 3044: 3037: 3020: 3007: 3003: 2989: 2975: 2958: 2956: 2955: 2950: 2948: 2937: 2927: 2911: 2909: 2908: 2903: 2879: 2877: 2876: 2871: 2859: 2857: 2856: 2851: 2839: 2837: 2836: 2831: 2819: 2817: 2816: 2811: 2795: 2793: 2792: 2787: 2785: 2784: 2768: 2766: 2765: 2760: 2758: 2754: 2741: 2740: 2731: 2730: 2721: 2720: 2681: 2679: 2678: 2673: 2647: 2645: 2644: 2639: 2613: 2611: 2610: 2605: 2579: 2577: 2576: 2571: 2540: 2538: 2537: 2532: 2520: 2518: 2517: 2512: 2500: 2498: 2497: 2492: 2490: 2486: 2452: 2450: 2449: 2444: 2442: 2438: 2410: 2408: 2407: 2402: 2373: 2371: 2370: 2365: 2349: 2347: 2346: 2341: 2311:semi-Thue system 2308: 2306: 2305: 2300: 2254: 2252: 2251: 2246: 2234: 2232: 2231: 2226: 2215: 2203: 2201: 2200: 2195: 2172: 2170: 2169: 2164: 2162: 2161: 2145: 2143: 2142: 2137: 2135: 2131: 2127: 2114: 2106: 2105: 2066: 2064: 2063: 2058: 2046: 2044: 2043: 2038: 2036: 2035: 2001: 1999: 1998: 1993: 1991: 1966: 1964: 1963: 1958: 1956: 1943: 1930: 1928: 1927: 1922: 1848: 1847: 1791: 1769: 1767: 1766: 1761: 1759: 1758: 1730: 1728: 1727: 1722: 1720: 1703: 1701: 1700: 1695: 1654:Given a grammar 1636:rewriting system 1633: 1631: 1630: 1625: 1574: 1572: 1571: 1566: 1543: 1541: 1540: 1535: 1519: 1517: 1516: 1511: 1491: 1489: 1488: 1483: 1467: 1465: 1464: 1459: 1457: 1441: 1439: 1438: 1433: 1431: 1430: 1406: 1405: 1381: 1380: 1345:production rules 1325:terminal symbols 1321: 1319: 1318: 1313: 1249: 1247: 1246: 1241: 1221: 1219: 1218: 1213: 1193: 1191: 1190: 1185: 1162: 1160: 1159: 1154: 1122: 1120: 1119: 1114: 1102: 1100: 1099: 1094: 1082: 1080: 1079: 1074: 1062: 1060: 1059: 1054: 1042: 1040: 1039: 1034: 1016: 1014: 1013: 1008: 996: 994: 993: 988: 976: 974: 973: 968: 956: 954: 953: 948: 933: 931: 930: 925: 910: 908: 907: 902: 876: 874: 873: 868: 845: 843: 842: 837: 812:Examples 2 and 3 803: 801: 800: 795: 783: 781: 780: 775: 763: 761: 760: 755: 743: 741: 740: 735: 733: 732: 716: 714: 713: 708: 607: 606: 591: 590: 568: 566: 565: 560: 462: 460: 459: 454: 431: 429: 428: 423: 348:semi-Thue system 332:production rules 275:formal semantics 256:production rules 224: 217: 210: 53:Formal languages 38: 21: 7418: 7417: 7413: 7412: 7411: 7409: 7408: 7407: 7373: 7372: 7371: 7366: 7355: 7348: 7293:Category theory 7283:Algebraic logic 7266: 7237:Lambda calculus 7175:Church encoding 7161: 7137:Truth predicate 6993: 6959:Complete theory 6882: 6751: 6747: 6743: 6738: 6730: 6450: and  6446: 6441: 6427: 6403:New Foundations 6371:axiom of choice 6354: 6316:Gödel numbering 6256: and  6248: 6152: 6037: 5987: 5968: 5917:Boolean algebra 5903: 5867:Equiconsistency 5832:Classical logic 5809: 5790:Halting problem 5778: and  5754: and  5742: and  5741: 5736:Theorems ( 5731: 5648: 5643: 5613: 5608: 5605: 5598: 5592: 5587: 5509: 5453: 5432: 5378: 5359: 5282: 5280:formal grammars 5272:Automata theory 5269: 5239: 5234: 5233: 5222: 5218: 5209: 5205: 5196: 5192: 5181: 5177: 5163: 5162: 5158: 5149:Wayback Machine 5140: 5136: 5127: 5123: 5110: 5106: 5097: 5093: 5076: 5072: 5047: 5046: 5042: 5032:Wayback Machine 5022: 5018: 5009: 5005: 4999:Wayback Machine 4990: 4986: 4979: 4963: 4962: 4958: 4951: 4935: 4934: 4930: 4916: 4915: 4911: 4879: 4878: 4871: 4860: 4845: 4844: 4840: 4835: 4830: 4756: 4691: 4659: 4652: 4621: 4584: 4583: 4553: 4552: 4523: 4522: 4493: 4492: 4463: 4462: 4433: 4432: 4408: 4407: 4381: 4377: 4366: 4365: 4333: 4329: 4318: 4317: 4296: 4291: 4290: 4271: 4270: 4251: 4250: 4206: 4196: 4195: 4191: 4186: 4185: 4147: 4137: 4136: 4132: 4127: 4126: 4112: 4084: 4083: 4059: 4048: 4047: 4012: 4001: 4000: 3969: 3968: 3935: 3934: 3911: 3910: 3884: 3880: 3869: 3868: 3846: 3835: 3834: 3813: 3808: 3807: 3788: 3787: 3768: 3767: 3729: 3719: 3718: 3714: 3709: 3708: 3666: 3656: 3646: 3645: 3641: 3621: 3620: 3603: 3543: 3535:Main articles: 3533: 3523: 3519: 3515: 3483: 3482: 3478: 3463: 3462: 3378: 3377: 3254: 3253: 3208: 3207: 3146: 3132: 3131: 3116: 3115: 3079: 3078: 3042: 3041: 3005: 3004: 2976: 2962: 2961: 2918: 2917: 2885: 2884: 2862: 2861: 2842: 2841: 2822: 2821: 2802: 2801: 2776: 2771: 2770: 2732: 2722: 2712: 2711: 2707: 2687: 2686: 2652: 2651: 2618: 2617: 2584: 2583: 2547: 2546: 2523: 2522: 2503: 2502: 2470: 2466: 2455: 2454: 2428: 2424: 2413: 2412: 2393: 2392: 2380: 2356: 2355: 2314: 2313: 2261: 2260: 2237: 2236: 2206: 2205: 2186: 2185: 2153: 2148: 2147: 2097: 2078: 2074: 2069: 2068: 2049: 2048: 2027: 2010: 2009: 2008:is a member of 2006:sentential form 1977: 1976: 1967:(pronounced as 1937: 1936: 1839: 1774: 1773: 1770:is defined by: 1750: 1733: 1732: 1706: 1705: 1656: 1655: 1648: 1592: 1591: 1581:sentence symbol 1551: 1550: 1526: 1525: 1502: 1501: 1474: 1473: 1448: 1447: 1422: 1397: 1372: 1355: 1354: 1304: 1303: 1267: 1262: 1256: 1226: 1225: 1198: 1197: 1167: 1166: 1136: 1135: 1105: 1104: 1085: 1084: 1065: 1064: 1045: 1044: 1019: 1018: 999: 998: 979: 978: 959: 958: 939: 938: 916: 915: 881: 880: 850: 849: 822: 821: 814: 786: 785: 766: 765: 746: 745: 724: 719: 718: 598: 582: 574: 573: 500: 499: 436: 435: 402: 401: 394: 341:right-hand side 327: 295:automata theory 244:formal language 228: 199: 198: 184:Syntax analysis 159:Predicate logic 144: 143: 134: 133: 109:Automata theory 64: 63: 36: 23: 22: 18:Sentential form 15: 12: 11: 5: 7416: 7414: 7406: 7405: 7400: 7395: 7390: 7385: 7375: 7374: 7368: 7367: 7353: 7350: 7349: 7347: 7346: 7341: 7336: 7331: 7326: 7325: 7324: 7314: 7309: 7304: 7295: 7290: 7285: 7280: 7278:Abstract logic 7274: 7272: 7268: 7267: 7265: 7264: 7259: 7257:Turing machine 7254: 7249: 7244: 7239: 7234: 7229: 7228: 7227: 7222: 7217: 7212: 7207: 7197: 7195:Computable set 7192: 7187: 7182: 7177: 7171: 7169: 7163: 7162: 7160: 7159: 7154: 7149: 7144: 7139: 7134: 7129: 7124: 7123: 7122: 7117: 7112: 7102: 7097: 7092: 7090:Satisfiability 7087: 7082: 7077: 7076: 7075: 7065: 7064: 7063: 7053: 7052: 7051: 7046: 7041: 7036: 7031: 7021: 7020: 7019: 7014: 7007:Interpretation 7003: 7001: 6995: 6994: 6992: 6991: 6986: 6981: 6976: 6971: 6961: 6956: 6955: 6954: 6953: 6952: 6942: 6937: 6927: 6922: 6917: 6912: 6907: 6902: 6896: 6894: 6888: 6887: 6884: 6883: 6881: 6880: 6872: 6871: 6870: 6869: 6864: 6863: 6862: 6857: 6852: 6832: 6831: 6830: 6828:minimal axioms 6825: 6814: 6813: 6812: 6801: 6800: 6799: 6794: 6789: 6784: 6779: 6774: 6761: 6759: 6740: 6739: 6737: 6736: 6735: 6734: 6722: 6717: 6716: 6715: 6710: 6705: 6700: 6690: 6685: 6680: 6675: 6674: 6673: 6668: 6658: 6657: 6656: 6651: 6646: 6641: 6631: 6626: 6625: 6624: 6619: 6614: 6604: 6603: 6602: 6597: 6592: 6587: 6582: 6577: 6567: 6562: 6557: 6552: 6551: 6550: 6545: 6540: 6535: 6525: 6520: 6518:Formation rule 6515: 6510: 6509: 6508: 6503: 6493: 6492: 6491: 6481: 6476: 6471: 6466: 6460: 6454: 6437:Formal systems 6433: 6432: 6429: 6428: 6426: 6425: 6420: 6415: 6410: 6405: 6400: 6395: 6390: 6385: 6380: 6379: 6378: 6373: 6362: 6360: 6356: 6355: 6353: 6352: 6351: 6350: 6340: 6335: 6334: 6333: 6326:Large cardinal 6323: 6318: 6313: 6308: 6303: 6289: 6288: 6287: 6282: 6277: 6262: 6260: 6250: 6249: 6247: 6246: 6245: 6244: 6239: 6234: 6224: 6219: 6214: 6209: 6204: 6199: 6194: 6189: 6184: 6179: 6174: 6169: 6163: 6161: 6154: 6153: 6151: 6150: 6149: 6148: 6143: 6138: 6133: 6128: 6123: 6115: 6114: 6113: 6108: 6098: 6093: 6091:Extensionality 6088: 6086:Ordinal number 6083: 6073: 6068: 6067: 6066: 6055: 6049: 6043: 6042: 6039: 6038: 6036: 6035: 6030: 6025: 6020: 6015: 6010: 6005: 6004: 6003: 5993: 5992: 5991: 5978: 5976: 5970: 5969: 5967: 5966: 5965: 5964: 5959: 5954: 5944: 5939: 5934: 5929: 5924: 5919: 5913: 5911: 5905: 5904: 5902: 5901: 5896: 5891: 5886: 5881: 5876: 5871: 5870: 5869: 5859: 5854: 5849: 5844: 5839: 5834: 5828: 5826: 5817: 5811: 5810: 5808: 5807: 5802: 5797: 5792: 5787: 5782: 5770:Cantor's  5768: 5763: 5758: 5748: 5746: 5733: 5732: 5730: 5729: 5724: 5719: 5714: 5709: 5704: 5699: 5694: 5689: 5684: 5679: 5674: 5669: 5668: 5667: 5656: 5654: 5650: 5649: 5644: 5642: 5641: 5634: 5627: 5619: 5610: 5609: 5597: 5594: 5593: 5589: 5588: 5586: 5585: 5583:Acyclic finite 5580: 5575: 5570: 5565: 5560: 5555: 5550: 5544: 5539: 5534: 5533:Turing Machine 5528: 5526:Linear-bounded 5523: 5518: 5516:Turing machine 5512: 5510: 5508: 5507: 5502: 5497: 5492: 5487: 5482: 5477: 5475:Tree-adjoining 5472: 5467: 5464: 5459: 5451: 5446: 5441: 5435: 5433: 5431: 5430: 5425: 5422: 5417: 5412: 5407: 5402: 5400:Tree-adjoining 5397: 5392: 5389: 5384: 5376: 5371: 5368: 5362: 5360: 5358: 5357: 5354: 5351: 5348: 5345: 5342: 5339: 5336: 5333: 5330: 5327: 5324: 5321: 5318: 5314: 5311: 5310: 5305: 5300: 5295: 5287: 5284: 5283: 5270: 5268: 5267: 5260: 5253: 5245: 5238: 5237:External links 5235: 5232: 5231: 5216: 5203: 5190: 5175: 5156: 5134: 5121: 5104: 5091: 5070: 5059:(6): 607–639. 5040: 5023:Earley, Jay, " 5016: 5003: 4984: 4977: 4956: 4949: 4928: 4909: 4890:(3): 113–124. 4869: 4858: 4837: 4836: 4834: 4831: 4829: 4828: 4823: 4818: 4813: 4808: 4803: 4798: 4793: 4788: 4783: 4778: 4773: 4768: 4763: 4757: 4755: 4752: 4751: 4750: 4739:expressiveness 4732: 4722: 4701:by means of a 4690: 4687: 4671:left-recursive 4651: 4648: 4647: 4646: 4639:Affix grammars 4636: 4620: 4617: 4600: 4597: 4594: 4591: 4580: 4579: 4578: 4577: 4566: 4563: 4560: 4550: 4539: 4536: 4533: 4530: 4520: 4509: 4506: 4503: 4500: 4490: 4479: 4476: 4473: 4470: 4460: 4449: 4446: 4443: 4440: 4415: 4394: 4390: 4387: 4384: 4380: 4376: 4373: 4352: 4348: 4345: 4342: 4339: 4336: 4332: 4328: 4325: 4303: 4299: 4278: 4258: 4237: 4233: 4230: 4227: 4224: 4221: 4218: 4213: 4209: 4203: 4199: 4194: 4172: 4168: 4165: 4162: 4159: 4154: 4150: 4144: 4140: 4135: 4111: 4108: 4091: 4071: 4066: 4062: 4058: 4055: 4040:Big O notation 4024: 4019: 4015: 4011: 4008: 3997: 3996: 3985: 3982: 3979: 3976: 3965: 3954: 3951: 3948: 3945: 3942: 3918: 3897: 3893: 3890: 3887: 3883: 3879: 3876: 3855: 3852: 3849: 3845: 3842: 3820: 3816: 3795: 3775: 3754: 3750: 3747: 3744: 3741: 3736: 3732: 3726: 3722: 3717: 3691: 3687: 3684: 3681: 3678: 3673: 3669: 3663: 3659: 3653: 3649: 3644: 3640: 3637: 3634: 3631: 3628: 3602: 3599: 3583:Turing machine 3532: 3529: 3528: 3527: 3514:reads "String 3503: 3498: 3495: 3490: 3481:(On notation: 3477: 3476: 3461: 3458: 3455: 3452: 3448: 3445: 3441: 3438: 3435: 3430: 3427: 3422: 3419: 3416: 3412: 3409: 3405: 3402: 3399: 3396: 3391: 3388: 3383: 3381: 3379: 3376: 3373: 3370: 3367: 3364: 3360: 3357: 3353: 3350: 3345: 3342: 3337: 3334: 3331: 3328: 3324: 3321: 3317: 3314: 3311: 3306: 3303: 3298: 3295: 3292: 3289: 3286: 3283: 3279: 3276: 3272: 3267: 3264: 3259: 3257: 3255: 3252: 3249: 3245: 3242: 3239: 3235: 3232: 3229: 3226: 3221: 3218: 3213: 3211: 3209: 3206: 3202: 3199: 3196: 3193: 3189: 3186: 3181: 3178: 3172: 3169: 3166: 3163: 3157: 3154: 3149: 3147: 3144: 3140: 3139: 3129: 3114: 3111: 3107: 3104: 3100: 3097: 3092: 3089: 3084: 3082: 3080: 3077: 3074: 3071: 3067: 3064: 3060: 3055: 3052: 3047: 3045: 3043: 3040: 3036: 3033: 3030: 3026: 3023: 3018: 3015: 3010: 3008: 3006: 3002: 2999: 2996: 2993: 2987: 2984: 2979: 2977: 2974: 2970: 2969: 2959: 2947: 2944: 2941: 2935: 2932: 2926: 2914: 2901: 2898: 2895: 2892: 2869: 2849: 2829: 2809: 2783: 2779: 2757: 2753: 2750: 2747: 2744: 2739: 2735: 2729: 2725: 2719: 2715: 2710: 2706: 2703: 2700: 2697: 2694: 2683: 2682: 2671: 2668: 2665: 2662: 2659: 2648: 2637: 2634: 2631: 2628: 2625: 2614: 2603: 2600: 2597: 2594: 2591: 2580: 2569: 2566: 2563: 2560: 2557: 2554: 2530: 2510: 2489: 2485: 2482: 2479: 2476: 2473: 2469: 2465: 2462: 2441: 2437: 2434: 2431: 2427: 2423: 2420: 2400: 2379: 2376: 2363: 2339: 2336: 2333: 2330: 2327: 2324: 2321: 2298: 2295: 2292: 2289: 2286: 2283: 2280: 2277: 2274: 2271: 2268: 2257: 2256: 2244: 2224: 2221: 2218: 2214: 2193: 2178: 2173:) is called a 2160: 2156: 2134: 2130: 2125: 2121: 2118: 2112: 2109: 2104: 2100: 2096: 2093: 2090: 2087: 2084: 2081: 2077: 2056: 2034: 2030: 2026: 2023: 2020: 2017: 2002: 1989: 1986: 1954: 1950: 1947: 1933: 1932: 1931: 1920: 1917: 1914: 1911: 1908: 1905: 1902: 1899: 1896: 1893: 1890: 1887: 1884: 1881: 1878: 1875: 1872: 1869: 1866: 1863: 1860: 1857: 1854: 1851: 1846: 1842: 1838: 1835: 1832: 1829: 1826: 1823: 1820: 1817: 1814: 1811: 1808: 1805: 1802: 1798: 1794: 1789: 1786: 1781: 1757: 1753: 1749: 1746: 1743: 1740: 1718: 1715: 1693: 1690: 1687: 1684: 1681: 1678: 1675: 1672: 1669: 1666: 1663: 1647: 1644: 1623: 1620: 1617: 1614: 1611: 1608: 1605: 1602: 1599: 1585: 1584: 1564: 1561: 1558: 1546: 1545: 1533: 1509: 1481: 1456: 1444: 1443: 1442: 1429: 1425: 1421: 1418: 1415: 1412: 1409: 1404: 1400: 1396: 1393: 1390: 1387: 1384: 1379: 1375: 1371: 1368: 1365: 1362: 1349: 1348: 1337: 1311: 1300: 1266: 1263: 1258:Main article: 1255: 1252: 1251: 1250: 1239: 1236: 1233: 1222: 1211: 1208: 1205: 1194: 1183: 1180: 1177: 1174: 1163: 1152: 1149: 1146: 1143: 1123:as we please. 1112: 1092: 1072: 1052: 1032: 1029: 1026: 1006: 986: 966: 946: 923: 912: 911: 900: 897: 894: 891: 888: 877: 866: 863: 860: 857: 846: 835: 832: 829: 813: 810: 793: 773: 753: 731: 727: 706: 703: 700: 697: 694: 691: 688: 685: 682: 679: 676: 673: 670: 667: 664: 661: 658: 655: 652: 649: 646: 643: 640: 637: 634: 631: 628: 625: 622: 619: 616: 613: 610: 605: 601: 597: 594: 589: 585: 581: 558: 555: 552: 549: 546: 543: 540: 537: 534: 531: 528: 525: 522: 519: 516: 513: 510: 507: 464: 463: 452: 449: 446: 443: 432: 421: 418: 415: 412: 409: 393: 390: 337:left-hand side 326: 323: 315:deep structure 236:formal grammar 230: 229: 227: 226: 219: 212: 204: 201: 200: 197: 196: 191: 186: 181: 176: 171: 166: 161: 156: 151: 149:Formal methods 145: 141: 140: 139: 136: 135: 132: 131: 129:Atomic formula 126: 121: 116: 111: 106: 101: 99:Formation rule 96: 94:Formal grammar 91: 86: 81: 76: 71: 65: 61: 60: 59: 56: 55: 49: 48: 34: 24: 14: 13: 10: 9: 6: 4: 3: 2: 7415: 7404: 7401: 7399: 7396: 7394: 7391: 7389: 7386: 7384: 7381: 7380: 7378: 7365: 7364: 7359: 7351: 7345: 7342: 7340: 7337: 7335: 7332: 7330: 7327: 7323: 7320: 7319: 7318: 7315: 7313: 7310: 7308: 7305: 7303: 7299: 7296: 7294: 7291: 7289: 7286: 7284: 7281: 7279: 7276: 7275: 7273: 7269: 7263: 7260: 7258: 7255: 7253: 7252:Recursive set 7250: 7248: 7245: 7243: 7240: 7238: 7235: 7233: 7230: 7226: 7223: 7221: 7218: 7216: 7213: 7211: 7208: 7206: 7203: 7202: 7201: 7198: 7196: 7193: 7191: 7188: 7186: 7183: 7181: 7178: 7176: 7173: 7172: 7170: 7168: 7164: 7158: 7155: 7153: 7150: 7148: 7145: 7143: 7140: 7138: 7135: 7133: 7130: 7128: 7125: 7121: 7118: 7116: 7113: 7111: 7108: 7107: 7106: 7103: 7101: 7098: 7096: 7093: 7091: 7088: 7086: 7083: 7081: 7078: 7074: 7071: 7070: 7069: 7066: 7062: 7061:of arithmetic 7059: 7058: 7057: 7054: 7050: 7047: 7045: 7042: 7040: 7037: 7035: 7032: 7030: 7027: 7026: 7025: 7022: 7018: 7015: 7013: 7010: 7009: 7008: 7005: 7004: 7002: 7000: 6996: 6990: 6987: 6985: 6982: 6980: 6977: 6975: 6972: 6969: 6968:from ZFC 6965: 6962: 6960: 6957: 6951: 6948: 6947: 6946: 6943: 6941: 6938: 6936: 6933: 6932: 6931: 6928: 6926: 6923: 6921: 6918: 6916: 6913: 6911: 6908: 6906: 6903: 6901: 6898: 6897: 6895: 6893: 6889: 6879: 6878: 6874: 6873: 6868: 6867:non-Euclidean 6865: 6861: 6858: 6856: 6853: 6851: 6850: 6846: 6845: 6843: 6840: 6839: 6837: 6833: 6829: 6826: 6824: 6821: 6820: 6819: 6815: 6811: 6808: 6807: 6806: 6802: 6798: 6795: 6793: 6790: 6788: 6785: 6783: 6780: 6778: 6775: 6773: 6770: 6769: 6767: 6763: 6762: 6760: 6755: 6749: 6744:Example  6741: 6733: 6728: 6727: 6726: 6723: 6721: 6718: 6714: 6711: 6709: 6706: 6704: 6701: 6699: 6696: 6695: 6694: 6691: 6689: 6686: 6684: 6681: 6679: 6676: 6672: 6669: 6667: 6664: 6663: 6662: 6659: 6655: 6652: 6650: 6647: 6645: 6642: 6640: 6637: 6636: 6635: 6632: 6630: 6627: 6623: 6620: 6618: 6615: 6613: 6610: 6609: 6608: 6605: 6601: 6598: 6596: 6593: 6591: 6588: 6586: 6583: 6581: 6578: 6576: 6573: 6572: 6571: 6568: 6566: 6563: 6561: 6558: 6556: 6553: 6549: 6546: 6544: 6541: 6539: 6536: 6534: 6531: 6530: 6529: 6526: 6524: 6521: 6519: 6516: 6514: 6511: 6507: 6504: 6502: 6501:by definition 6499: 6498: 6497: 6494: 6490: 6487: 6486: 6485: 6482: 6480: 6477: 6475: 6472: 6470: 6467: 6465: 6462: 6461: 6458: 6455: 6453: 6449: 6444: 6438: 6434: 6424: 6421: 6419: 6416: 6414: 6411: 6409: 6406: 6404: 6401: 6399: 6396: 6394: 6391: 6389: 6388:Kripke–Platek 6386: 6384: 6381: 6377: 6374: 6372: 6369: 6368: 6367: 6364: 6363: 6361: 6357: 6349: 6346: 6345: 6344: 6341: 6339: 6336: 6332: 6329: 6328: 6327: 6324: 6322: 6319: 6317: 6314: 6312: 6309: 6307: 6304: 6301: 6297: 6293: 6290: 6286: 6283: 6281: 6278: 6276: 6273: 6272: 6271: 6267: 6264: 6263: 6261: 6259: 6255: 6251: 6243: 6240: 6238: 6235: 6233: 6232:constructible 6230: 6229: 6228: 6225: 6223: 6220: 6218: 6215: 6213: 6210: 6208: 6205: 6203: 6200: 6198: 6195: 6193: 6190: 6188: 6185: 6183: 6180: 6178: 6175: 6173: 6170: 6168: 6165: 6164: 6162: 6160: 6155: 6147: 6144: 6142: 6139: 6137: 6134: 6132: 6129: 6127: 6124: 6122: 6119: 6118: 6116: 6112: 6109: 6107: 6104: 6103: 6102: 6099: 6097: 6094: 6092: 6089: 6087: 6084: 6082: 6078: 6074: 6072: 6069: 6065: 6062: 6061: 6060: 6057: 6056: 6053: 6050: 6048: 6044: 6034: 6031: 6029: 6026: 6024: 6021: 6019: 6016: 6014: 6011: 6009: 6006: 6002: 5999: 5998: 5997: 5994: 5990: 5985: 5984: 5983: 5980: 5979: 5977: 5975: 5971: 5963: 5960: 5958: 5955: 5953: 5950: 5949: 5948: 5945: 5943: 5940: 5938: 5935: 5933: 5930: 5928: 5925: 5923: 5920: 5918: 5915: 5914: 5912: 5910: 5909:Propositional 5906: 5900: 5897: 5895: 5892: 5890: 5887: 5885: 5882: 5880: 5877: 5875: 5872: 5868: 5865: 5864: 5863: 5860: 5858: 5855: 5853: 5850: 5848: 5845: 5843: 5840: 5838: 5837:Logical truth 5835: 5833: 5830: 5829: 5827: 5825: 5821: 5818: 5816: 5812: 5806: 5803: 5801: 5798: 5796: 5793: 5791: 5788: 5786: 5783: 5781: 5777: 5773: 5769: 5767: 5764: 5762: 5759: 5757: 5753: 5750: 5749: 5747: 5745: 5739: 5734: 5728: 5725: 5723: 5720: 5718: 5715: 5713: 5710: 5708: 5705: 5703: 5700: 5698: 5695: 5693: 5690: 5688: 5685: 5683: 5680: 5678: 5675: 5673: 5670: 5666: 5663: 5662: 5661: 5658: 5657: 5655: 5651: 5647: 5640: 5635: 5633: 5628: 5626: 5621: 5620: 5617: 5602: 5601:proper subset 5595: 5584: 5581: 5579: 5576: 5574: 5571: 5569: 5566: 5564: 5561: 5559: 5556: 5554: 5551: 5549: 5545: 5543: 5540: 5538: 5535: 5532: 5529: 5527: 5524: 5522: 5519: 5517: 5514: 5513: 5511: 5506: 5503: 5501: 5498: 5496: 5493: 5491: 5488: 5486: 5483: 5481: 5478: 5476: 5473: 5471: 5468: 5465: 5463: 5460: 5457: 5452: 5450: 5447: 5445: 5442: 5440: 5437: 5436: 5434: 5429: 5428:Non-recursive 5426: 5423: 5421: 5418: 5416: 5413: 5411: 5408: 5406: 5403: 5401: 5398: 5396: 5393: 5390: 5388: 5385: 5382: 5377: 5375: 5372: 5369: 5367: 5364: 5363: 5361: 5355: 5352: 5349: 5346: 5343: 5340: 5337: 5334: 5331: 5328: 5325: 5322: 5319: 5316: 5315: 5313: 5312: 5309: 5306: 5304: 5301: 5299: 5296: 5294: 5291: 5290: 5285: 5281: 5277: 5273: 5266: 5261: 5259: 5254: 5252: 5247: 5246: 5243: 5236: 5228: 5227: 5223:Ford, Bryan, 5220: 5217: 5213: 5207: 5204: 5200: 5194: 5191: 5187: 5186: 5179: 5176: 5171: 5167: 5160: 5157: 5154: 5150: 5146: 5143: 5138: 5135: 5131: 5125: 5122: 5118: 5114: 5108: 5105: 5101: 5095: 5092: 5088: 5084: 5080: 5074: 5071: 5066: 5062: 5058: 5054: 5050: 5044: 5041: 5037: 5033: 5029: 5026: 5020: 5017: 5013: 5007: 5004: 5000: 4996: 4993: 4988: 4985: 4980: 4974: 4970: 4966: 4960: 4957: 4952: 4946: 4942: 4938: 4932: 4929: 4924: 4921:. The Hague: 4920: 4913: 4910: 4905: 4901: 4897: 4893: 4889: 4885: 4884: 4876: 4874: 4870: 4866: 4861: 4859:9781466513457 4855: 4851: 4850: 4842: 4839: 4832: 4827: 4824: 4822: 4821:Shape grammar 4819: 4817: 4814: 4812: 4809: 4807: 4804: 4802: 4799: 4797: 4794: 4792: 4789: 4787: 4784: 4782: 4779: 4777: 4774: 4772: 4769: 4767: 4764: 4762: 4759: 4758: 4753: 4748: 4744: 4740: 4736: 4733: 4730: 4726: 4725:Link grammars 4723: 4720: 4716: 4713: 4712: 4711: 4707: 4704: 4700: 4696: 4688: 4686: 4684: 4680: 4676: 4672: 4668: 4664: 4657: 4649: 4644: 4640: 4637: 4634: 4630: 4627: 4626: 4625: 4618: 4616: 4614: 4595: 4589: 4564: 4558: 4551: 4537: 4534: 4528: 4521: 4507: 4504: 4498: 4491: 4477: 4474: 4468: 4461: 4447: 4444: 4438: 4431: 4430: 4429: 4428: 4427: 4413: 4392: 4388: 4385: 4382: 4378: 4374: 4350: 4346: 4343: 4340: 4337: 4334: 4330: 4326: 4323: 4301: 4297: 4276: 4256: 4235: 4231: 4228: 4225: 4222: 4219: 4216: 4211: 4207: 4201: 4197: 4192: 4170: 4166: 4163: 4160: 4157: 4152: 4148: 4142: 4138: 4133: 4125:The language 4123: 4121: 4117: 4109: 4107: 4105: 4089: 4064: 4060: 4053: 4045: 4041: 4038: 4017: 4013: 4006: 3983: 3980: 3974: 3966: 3952: 3949: 3946: 3940: 3932: 3931: 3930: 3916: 3895: 3891: 3888: 3885: 3881: 3877: 3853: 3850: 3847: 3843: 3840: 3818: 3814: 3793: 3773: 3752: 3748: 3745: 3742: 3739: 3734: 3730: 3724: 3720: 3715: 3706: 3689: 3685: 3682: 3679: 3676: 3671: 3667: 3661: 3657: 3651: 3647: 3642: 3638: 3632: 3626: 3619:The language 3617: 3615: 3610: 3609: 3600: 3598: 3596: 3592: 3588: 3584: 3580: 3576: 3575: 3570: 3569: 3564: 3563: 3559:(Type 2) and 3558: 3557: 3552: 3548: 3542: 3538: 3530: 3501: 3496: 3488: 3480: 3479: 3459: 3456: 3453: 3450: 3439: 3436: 3433: 3428: 3420: 3417: 3414: 3403: 3400: 3397: 3394: 3389: 3382: 3374: 3371: 3368: 3365: 3362: 3351: 3348: 3343: 3335: 3332: 3329: 3326: 3315: 3312: 3309: 3304: 3296: 3293: 3290: 3287: 3284: 3281: 3270: 3265: 3258: 3250: 3247: 3233: 3230: 3227: 3224: 3219: 3212: 3204: 3187: 3184: 3179: 3155: 3148: 3130: 3112: 3109: 3098: 3095: 3090: 3083: 3075: 3072: 3069: 3058: 3053: 3046: 3038: 3024: 3021: 3016: 3009: 2985: 2978: 2960: 2933: 2916: 2915: 2913: 2896: 2890: 2881: 2867: 2847: 2827: 2807: 2799: 2781: 2777: 2755: 2751: 2748: 2745: 2742: 2737: 2733: 2727: 2723: 2717: 2713: 2708: 2704: 2698: 2692: 2669: 2666: 2660: 2657: 2649: 2635: 2632: 2626: 2623: 2615: 2601: 2598: 2595: 2589: 2581: 2567: 2564: 2561: 2558: 2552: 2544: 2543: 2542: 2528: 2508: 2487: 2483: 2480: 2477: 2474: 2471: 2467: 2463: 2439: 2435: 2432: 2429: 2425: 2421: 2418: 2398: 2389: 2388: 2386: 2377: 2375: 2361: 2353: 2334: 2331: 2325: 2322: 2312: 2293: 2290: 2287: 2284: 2278: 2275: 2269: 2266: 2242: 2219: 2204:, denoted as 2191: 2183: 2179: 2176: 2158: 2132: 2128: 2123: 2119: 2110: 2107: 2102: 2094: 2091: 2082: 2079: 2075: 2054: 2032: 2024: 2021: 2007: 2003: 1987: 1974: 1970: 1952: 1948: 1935:the relation 1934: 1915: 1912: 1909: 1906: 1903: 1897: 1891: 1888: 1885: 1879: 1873: 1867: 1864: 1861: 1858: 1855: 1849: 1844: 1836: 1833: 1824: 1821: 1818: 1815: 1812: 1809: 1806: 1803: 1792: 1787: 1779: 1772: 1771: 1755: 1747: 1744: 1716: 1688: 1685: 1682: 1679: 1673: 1670: 1664: 1661: 1653: 1652: 1651: 1645: 1643: 1641: 1637: 1618: 1615: 1612: 1609: 1603: 1600: 1590: 1582: 1578: 1562: 1559: 1556: 1548: 1547: 1531: 1523: 1499: 1495: 1479: 1472:operator and 1471: 1454: 1445: 1427: 1419: 1416: 1402: 1394: 1391: 1382: 1377: 1369: 1366: 1353: 1352: 1351: 1350: 1346: 1342: 1339:A finite set 1338: 1335: 1331: 1327: 1326: 1302:A finite set 1301: 1298: 1294: 1290: 1289: 1284: 1281:A finite set 1280: 1279: 1278: 1276: 1272: 1264: 1261: 1253: 1237: 1231: 1223: 1209: 1203: 1195: 1181: 1178: 1172: 1164: 1150: 1147: 1141: 1133: 1132: 1131: 1129: 1124: 1110: 1090: 1070: 1050: 1030: 1027: 1024: 1004: 984: 964: 944: 935: 921: 898: 892: 889: 886: 878: 864: 861: 855: 847: 833: 827: 819: 818: 817: 811: 809: 807: 791: 771: 751: 729: 725: 701: 698: 695: 692: 689: 686: 683: 680: 677: 674: 671: 668: 665: 662: 659: 656: 653: 650: 647: 644: 641: 638: 635: 632: 629: 623: 617: 614: 611: 608: 603: 599: 595: 592: 587: 583: 570: 556: 553: 550: 547: 544: 541: 535: 532: 529: 526: 523: 517: 514: 511: 505: 497: 493: 489: 485: 481: 477: 473: 469: 450: 447: 441: 433: 419: 416: 413: 407: 399: 398: 397: 391: 389: 387: 383: 379: 374: 372: 366: 364: 360: 358: 354: 349: 344: 342: 338: 334: 333: 324: 322: 320: 316: 312: 308: 304: 300: 296: 292: 287: 282: 280: 276: 272: 268: 264: 259: 257: 253: 249: 245: 241: 237: 225: 220: 218: 213: 211: 206: 205: 203: 202: 195: 192: 190: 187: 185: 182: 180: 177: 175: 172: 170: 167: 165: 162: 160: 157: 155: 152: 150: 147: 146: 138: 137: 130: 127: 125: 122: 120: 117: 115: 112: 110: 107: 105: 102: 100: 97: 95: 92: 90: 87: 85: 82: 80: 77: 75: 72: 70: 69:Formal system 67: 66: 58: 57: 54: 50: 46: 45: 40: 39: 29: 19: 7354: 7152:Ultraproduct 6999:Model theory 6964:Independence 6900:Formal proof 6892:Proof theory 6875: 6848: 6805:real numbers 6777:second-order 6688:Substitution 6565:Metalanguage 6522: 6506:conservative 6479:Axiom schema 6423:Constructive 6393:Morse–Kelley 6359:Set theories 6338:Aleph number 6331:inaccessible 6237:Grothendieck 6121:intersection 6008:Higher-order 5996:Second-order 5942:Truth tables 5899:Venn diagram 5682:Formal proof 5537:Nested stack 5480:Context-free 5405:Context-free 5366:Unrestricted 5297: 5279: 5224: 5219: 5211: 5206: 5193: 5183: 5178: 5169: 5159: 5137: 5129: 5124: 5116: 5107: 5099: 5094: 5086: 5078: 5073: 5056: 5052: 5049:Knuth, D. E. 5043: 5035: 5019: 5011: 5006: 4987: 4968: 4959: 4940: 4931: 4918: 4912: 4887: 4881: 4848: 4841: 4708: 4702: 4698: 4692: 4678: 4674: 4660: 4622: 4581: 4249:(at least 1 4124: 4113: 4036: 3998: 3766:(at least 1 3618: 3613: 3606: 3604: 3572: 3566: 3560: 3554: 3547:Noam Chomsky 3544: 2882: 2800:consecutive 2797: 2684: 2390: 2382: 2381: 2351: 2259:The grammar 2258: 2181: 2174: 2005: 1968: 1649: 1586: 1580: 1577:start symbol 1576: 1575:that is the 1521: 1498:empty string 1344: 1340: 1333: 1323: 1296: 1286: 1282: 1274: 1271:Noam Chomsky 1268: 1125: 936: 913: 815: 806:context-free 571: 495: 491: 487: 483: 479: 475: 471: 467: 465: 395: 385: 381: 377: 375: 367: 363:start symbol 362: 356: 352: 345: 340: 336: 330: 328: 283: 260: 235: 233: 142:Applications 93: 62:Key concepts 43: 7262:Type theory 7210:undecidable 7142:Truth value 7029:equivalence 6708:non-logical 6321:Enumeration 6311:Isomorphism 6258:cardinality 6242:Von Neumann 6207:Ultrafilter 6172:Uncountable 6106:equivalence 6023:Quantifiers 6013:Fixed-point 5982:First-order 5862:Consistency 5847:Proposition 5824:Traditional 5795:Lindström's 5785:Compactness 5727:Type theory 5672:Cardinality 5546:restricted 4729:linguistics 4633:parse trees 2352:nonterminal 1470:Kleene star 784:times (and 353:nonterminal 7377:Categories 7073:elementary 6766:arithmetic 6634:Quantifier 6612:functional 6484:Expression 6202:Transitive 6146:identities 6131:complement 6064:hereditary 6047:Set theory 4833:References 4703:generative 3595:LR parsers 3591:LL parsers 1291:, that is 311:parse tree 291:recognizer 119:Production 7344:Supertask 7247:Recursion 7205:decidable 7039:saturated 7017:of models 6940:deductive 6935:axiomatic 6855:Hilbert's 6842:Euclidean 6823:canonical 6746:axiomatic 6678:Signature 6607:Predicate 6496:Extension 6418:Ackermann 6343:Operation 6222:Universal 6212:Recursive 6187:Singleton 6182:Inhabited 6167:Countable 6157:Types of 6141:power set 6111:partition 6028:Predicate 5974:Predicate 5889:Syllogism 5879:Soundness 5852:Inference 5842:Tautology 5744:paradoxes 5500:Star-free 5454:Positive 5444:Decidable 5379:Positive 5303:Languages 4741:needs of 4699:described 4663:recursive 4624:include: 4565:ϵ 4562:→ 4532:→ 4502:→ 4472:→ 4442:→ 4372:Σ 4229:≥ 4217:∣ 4164:≥ 4158:∣ 3978:→ 3944:→ 3875:Σ 3746:≥ 3740:∣ 3683:≥ 3677:∣ 3494:⇒ 3426:⇒ 3387:⇒ 3341:⇒ 3302:⇒ 3263:⇒ 3217:⇒ 3177:⇒ 3153:⇒ 3088:⇒ 3051:⇒ 3014:⇒ 2983:⇒ 2931:⇒ 2749:≥ 2743:∣ 2664:→ 2630:→ 2593:→ 2556:→ 2461:Σ 2329:Σ 2326:∪ 2282:Σ 2159:∗ 2155:Σ 2124:∗ 2117:⇒ 2108:∣ 2103:∗ 2092:∪ 2089:Σ 2083:∈ 2033:∗ 2022:∪ 2019:Σ 1985:⇒ 1953:∗ 1946:⇒ 1898:∧ 1889:∈ 1883:→ 1874:∧ 1845:∗ 1834:∪ 1831:Σ 1825:∈ 1801:∃ 1797:⟺ 1785:⇒ 1756:∗ 1745:∪ 1742:Σ 1714:⇒ 1677:Σ 1607:Σ 1560:∈ 1532:ϵ 1508:Λ 1494:set union 1480:∪ 1455:∗ 1428:∗ 1417:∪ 1414:Σ 1408:→ 1403:∗ 1392:∪ 1389:Σ 1378:∗ 1367:∪ 1364:Σ 1310:Σ 1235:→ 1207:→ 1176:→ 1145:→ 957:s and/or 896:→ 859:→ 831:→ 764:repeated 702:… 615:≥ 609:∣ 539:⇒ 521:⇒ 509:⇒ 445:→ 411:→ 392:Example 1 371:ambiguous 346:Unlike a 7329:Logicism 7322:timeline 7298:Concrete 7157:Validity 7127:T-schema 7120:Kripke's 7115:Tarski's 7110:semantic 7100:Strength 7049:submodel 7044:spectrum 7012:function 6860:Tarski's 6849:Elements 6836:geometry 6792:Robinson 6713:variable 6698:function 6671:spectrum 6661:Sentence 6617:variable 6560:Language 6513:Relation 6474:Automata 6464:Alphabet 6448:language 6302:-jection 6280:codomain 6266:Function 6227:Universe 6197:Infinite 6101:Relation 5884:Validity 5874:Argument 5772:theorem, 5298:Grammars 5145:Archived 5028:Archived 4995:Archived 4967:(1978). 4939:(1975). 4904:19519474 4806:L-system 4754:See also 4749:writers. 4747:compiler 2182:language 2175:sentence 1492:denotes 1330:disjoint 1328:that is 1293:disjoint 997:from an 717:, where 357:terminal 240:alphabet 74:Alphabet 44:a series 41:Part of 7388:Grammar 7271:Related 7068:Diagram 6966: ( 6945:Hilbert 6930:Systems 6925:Theorem 6803:of the 6748:systems 6528:Formula 6523:Grammar 6439: ( 6383:General 6096:Forcing 6081:Element 6001:Monadic 5776:paradox 5717:Theorem 5653:General 5521:Decider 5495:Regular 5462:Indexed 5420:Regular 5387:Indexed 4796:Grammar 2378:Example 1468:is the 1128:regular 359:symbols 299:Parsing 7398:Syntax 7034:finite 6797:Skolem 6750:  6725:Theory 6693:Symbol 6683:String 6666:atomic 6543:ground 6538:closed 6533:atomic 6489:ground 6452:syntax 6348:binary 6275:domain 6192:Finite 5957:finite 5815:Logics 5774:  5722:Theory 5573:Finite 5505:Finite 5350:Type-3 5341:Type-2 5323:Type-1 5317:Type-0 5079:et al. 4975:  4947:  4923:Mouton 4902:  4856:  4811:Lojban 4035:time ( 2912:are: 2769:where 2411:where 1446:where 496:aababb 248:syntax 79:Syntax 7024:Model 6772:Peano 6629:Proof 6469:Arity 6398:Naive 6285:image 6217:Fuzzy 6177:Empty 6126:union 6071:Class 5712:Model 5702:Lemma 5660:Axiom 5531:PTIME 5153:JPR02 4900:S2CID 4316:with 3833:with 3545:When 1638:or a 1589:tuple 1332:from 490:with 484:aaSbb 478:with 242:of a 7147:Type 6950:list 6754:list 6731:list 6720:Term 6654:rank 6548:open 6442:list 6254:Maps 6159:sets 6018:Free 5988:list 5738:list 5665:list 5278:and 4973:ISBN 4945:ISBN 4854:ISBN 4745:and 4641:and 3593:and 3571:and 3539:and 2880:'s. 2180:the 380:and 355:and 6834:of 6816:of 6764:of 6296:Sur 6270:Map 6077:Ur- 6059:Set 5115:," 5085:," 5081:, " 5061:doi 5034:," 4892:doi 4669:is 4114:In 4037:see 3967:2. 3933:1. 2650:4. 2616:3. 2582:2. 2545:1. 2184:of 1975:of 1524:or 1343:of 1322:of 1285:of 1224:4. 1196:3. 1165:2. 1134:1. 1103:or 934:s. 879:3. 848:2. 820:1. 744:is 480:aSb 472:aSb 434:2. 400:1. 321:). 317:in 303:set 286:set 7379:: 7220:NP 6844:: 6838:: 6768:: 6445:), 6300:Bi 6292:In 5274:: 5168:. 5055:. 4898:. 4886:. 4872:^ 4406:, 4364:, 3909:, 3867:, 3616:. 3605:A 2501:, 2453:, 2004:a 1520:, 569:. 492:ba 388:. 373:. 365:. 277:, 273:, 269:, 234:A 47:on 7300:/ 7215:P 6970:) 6756:) 6752:( 6649:∀ 6644:! 6639:∃ 6600:= 6595:↔ 6590:→ 6585:∧ 6580:∨ 6575:¬ 6298:/ 6294:/ 6268:/ 6079:) 6075:( 5962:∞ 5952:3 5740:) 5638:e 5631:t 5624:v 5466:— 5424:— 5391:— 5356:— 5353:— 5347:— 5344:— 5338:— 5335:— 5332:— 5329:— 5326:— 5320:— 5264:e 5257:t 5250:v 5067:. 5063:: 5057:8 4981:. 4953:. 4925:. 4906:. 4894:: 4888:2 4867:. 4721:. 4679:A 4675:A 4658:. 4599:) 4596:n 4593:( 4590:O 4559:B 4538:B 4535:b 4529:B 4508:B 4505:b 4499:A 4478:A 4475:a 4469:A 4448:A 4445:a 4439:S 4414:S 4393:} 4389:b 4386:, 4383:a 4379:{ 4375:= 4351:} 4347:B 4344:, 4341:A 4338:, 4335:S 4331:{ 4327:= 4324:N 4302:3 4298:G 4277:b 4257:a 4236:} 4232:1 4226:n 4223:, 4220:m 4212:m 4208:b 4202:n 4198:a 4193:{ 4171:} 4167:1 4161:n 4153:n 4149:b 4143:n 4139:a 4134:{ 4090:n 4070:) 4065:3 4061:n 4057:( 4054:O 4023:) 4018:3 4014:n 4010:( 4007:O 3984:b 3981:a 3975:S 3953:b 3950:S 3947:a 3941:S 3917:S 3896:} 3892:b 3889:, 3886:a 3882:{ 3878:= 3854:} 3851:S 3848:{ 3844:= 3841:N 3819:2 3815:G 3794:b 3774:a 3753:} 3749:1 3743:n 3735:n 3731:b 3725:n 3721:a 3716:{ 3690:} 3686:1 3680:n 3672:n 3668:c 3662:n 3658:b 3652:n 3648:a 3643:{ 3639:= 3636:) 3633:G 3630:( 3627:L 3524:i 3520:Q 3516:P 3502:Q 3497:i 3489:P 3460:c 3457:c 3454:c 3451:b 3447:b 3444:b 3440:a 3437:a 3434:a 3429:4 3421:c 3418:c 3415:c 3411:b 3408:b 3404:B 3401:a 3398:a 3395:a 3390:4 3375:c 3372:c 3369:c 3366:b 3363:B 3359:B 3356:a 3352:a 3349:a 3344:3 3336:c 3333:c 3330:c 3327:b 3323:B 3320:a 3316:B 3313:a 3310:a 3305:3 3297:c 3294:c 3291:c 3288:b 3285:a 3282:B 3278:B 3275:a 3271:a 3266:3 3251:c 3248:c 3244:c 3241:b 3238:a 3234:B 3231:a 3228:B 3225:a 3220:2 3205:c 3201:c 3198:S 3195:B 3192:a 3188:B 3185:a 3180:1 3171:c 3168:S 3165:B 3162:a 3156:1 3143:S 3113:c 3110:c 3106:b 3103:b 3099:a 3096:a 3091:4 3076:c 3073:c 3070:b 3066:B 3063:a 3059:a 3054:3 3039:c 3035:c 3032:b 3029:a 3025:B 3022:a 3017:2 3001:c 2998:S 2995:B 2992:a 2986:1 2973:S 2946:c 2943:b 2940:a 2934:2 2925:S 2900:) 2897:G 2894:( 2891:L 2868:c 2848:b 2828:a 2808:a 2798:n 2782:n 2778:a 2756:} 2752:1 2746:n 2738:n 2734:c 2728:n 2724:b 2718:n 2714:a 2709:{ 2705:= 2702:) 2699:G 2696:( 2693:L 2670:b 2667:b 2661:b 2658:B 2636:B 2633:a 2627:a 2624:B 2602:c 2599:b 2596:a 2590:S 2568:c 2565:S 2562:B 2559:a 2553:S 2529:P 2509:S 2488:} 2484:c 2481:, 2478:b 2475:, 2472:a 2468:{ 2464:= 2440:} 2436:B 2433:, 2430:S 2426:{ 2422:= 2419:N 2399:G 2387:. 2362:S 2338:) 2335:P 2332:, 2323:N 2320:( 2297:) 2294:S 2291:, 2288:P 2285:, 2279:, 2276:N 2273:( 2270:= 2267:G 2255:. 2243:G 2223:) 2220:G 2217:( 2213:L 2192:G 2177:. 2133:} 2129:w 2120:G 2111:S 2099:) 2095:N 2086:( 2080:w 2076:{ 2055:S 2029:) 2025:N 2016:( 1988:G 1949:G 1919:) 1916:v 1913:q 1910:u 1907:= 1904:y 1901:( 1895:) 1892:P 1886:q 1880:p 1877:( 1871:) 1868:v 1865:p 1862:u 1859:= 1856:x 1853:( 1850:: 1841:) 1837:N 1828:( 1822:q 1819:, 1816:p 1813:, 1810:v 1807:, 1804:u 1793:y 1788:G 1780:x 1752:) 1748:N 1739:( 1717:G 1692:) 1689:S 1686:, 1683:P 1680:, 1674:, 1671:N 1668:( 1665:= 1662:G 1622:) 1619:S 1616:, 1613:P 1610:, 1604:, 1601:N 1598:( 1583:. 1563:N 1557:S 1522:e 1424:) 1420:N 1411:( 1399:) 1395:N 1386:( 1383:N 1374:) 1370:N 1361:( 1341:P 1336:. 1334:N 1299:. 1297:G 1283:N 1275:G 1238:b 1232:S 1210:a 1204:S 1182:S 1179:b 1173:S 1151:S 1148:a 1142:S 1111:b 1091:a 1071:S 1051:b 1031:S 1028:S 1025:S 1005:S 985:b 965:b 945:a 922:S 899:b 893:a 890:S 887:a 865:S 862:S 856:S 834:a 828:S 792:n 772:k 752:a 730:k 726:a 705:} 699:, 696:b 693:b 690:b 687:a 684:b 681:a 678:a 675:a 672:, 669:b 666:b 663:a 660:b 657:a 654:a 651:, 648:b 645:a 642:b 639:a 636:, 633:a 630:b 627:{ 624:= 621:} 618:0 612:n 604:n 600:b 596:a 593:b 588:n 584:a 580:{ 557:b 554:b 551:a 548:b 545:a 542:a 536:b 533:b 530:S 527:a 524:a 518:b 515:S 512:a 506:S 488:S 476:S 468:S 451:a 448:b 442:S 420:b 417:S 414:a 408:S 386:S 382:b 378:a 289:" 223:e 216:t 209:v 20:)

Index

Sentential form

a series
Formal languages
Formal system
Alphabet
Syntax
Semantics (logic)
Semantics (programming languages)
Formal grammar
Formation rule
Well-formed formula
Automata theory
Regular expression
Production
Ground expression
Atomic formula
Formal methods
Propositional calculus
Predicate logic
Mathematical notation
Natural language processing
Programming language theory
Computational linguistics
Syntax analysis
Formal verification
Automated theorem proving
v
t
e

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