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Regular language

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398:"Kleene's theorem". Two other textbooks first prove the expressive equivalence of NFAs and DFAs ("2." and "3.") and then state "Kleene's theorem" as the equivalence between regular expressions and finite automata (the latter said to describe "recognizable languages"). A linguistically oriented text first equates regular grammars ("4." above) with DFAs and NFAs, calls the languages generated by (any of) these "regular", after which it introduces regular expressions which it terms to describe "rational languages", and finally states "Kleene's theorem" as the coincidence of regular and rational languages. Other authors simply 962: 397:
in textbooks. Precisely which one (or which subset) is called such varies between authors. One textbook calls the equivalence of regular expressions and NFAs ("1." and "2." above) "Kleene's theorem". Another textbook calls the equivalence of regular expressions and DFAs ("1." and "3." above)
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For a fixed finite alphabet, the theory of the set of all languages — together with strings, membership of a string in a language, and for each character, a function to append the character to a string (and no other operations) — is decidable, and its minimal
2293:. (In fact, Eilenberg defines rational and recognizable subsets of arbitrary monoids; the two notions do not, in general, coincide.) This terminology, while better motivated, never really caught on, and "regular language" is used almost universally.” 2246: 3696:: Representation of events in nerve nets and finite automata. In: Shannon, C.E., McCarthy, J. (eds.) Automata Studies, pp. 3–41. Princeton University Press, Princeton (1956); it is a slightly modified version of his 1951 1686: 229:≄ 0}. Intuitively, it cannot be recognized with a finite automaton, since a finite automaton has finite memory and it cannot remember the exact number of a's. Techniques to prove this fact rigorously are given 2289:'s monograph often use either the term "recognizable language", which refers to the behavior of automata, or "rational language", which refers to important analogies between regular expressions and rational 1840: 791:", still just regular languages can be described, but the universality problem has an exponential space lower bound, and is in fact complete for exponential space with respect to polynomial-time reduction. 1221: 2845:
M. Weyer: Chapter 12 - Decidability of S1S and S2S, p. 219, Theorem 12.26. In: Erich GrÀdel, Wolfgang Thomas, Thomas Wilke (Eds.): Automata, Logics, and Infinite Games: A Guide to Current Research.
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can be obtained by reversing all transitions and interchanging starting and finishing states. This may result in multiple starting states; Δ-transitions can be used to join them.
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over a monoid that is not necessarily free. Howard Straubing notes in relation to these facts that “The term "regular language" is a bit unfortunate. Papers influenced by
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Chapter 1: Regular Languages, pp. 31–90. Subsection "Decidable Problems Concerning Regular Languages" of section 4.1: Decidable Languages, pp. 152–155.
1766: 2034: 2014: 1926: 1570: 1550: 1256: 1117: 1097: 4094: 297: 3767: 1575: 2654: 845:, since it (trivially) contains the parity problem of determining whether the number of 1 bits in the input is even or odd and this problem is not in 3981: 3760: 3318:
Theoretical computer science: Introduction to Automata, Computability, Complexity, Algorithmics, Randomization, Communication, and Cryptography
1022:, those that can be described by a regular expression constructed from the empty symbol, letters, concatenation and all Boolean operators (see 379:
Properties 10. and 11. are purely algebraic approaches to define regular languages; a similar set of statements can be formulated for a monoid
3725: 3666: 3375: 3261: 3185: 2941: 2897: 2870: 2821: 2792: 2760: 2582: 3906: 2351: 3996: 2300: 990: 3921: 3136: 1774: 3620: 3590: 3582: 3326: 2846: 2726: 2703: 2664: 2632: 2493: 2395: 249: 4089: 4074: 402:"rational expression" and "regular expressions" as synonymous and do the same with "rational languages" and "regular languages". 3950: 812: 1136: 2391: 2332: 256: 1349: 38: 583:, inverse string homomorphism, and intersection with regular languages. As a consequence they are closed under arbitrary 3967: 3892: 1120: 576: 269: 45: 949:)) equals the class of regular languages. In practice, most nonregular problems are solved by machines taking at least 195:
language {Δ} = Ø* is regular. Other typical examples include the language consisting of all strings over the alphabet {
68:, in the strict sense in theoretical computer science (as opposed to many modern regular expression engines, which are 4064: 1308: 864: 104: 31: 2068: 390:
Some authors use one of the above properties different from "1." as an alternative definition of regular languages.
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Finite languages, those containing only a finite number of words. These are regular languages, as one can create a
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closure properties, the following problems are also decidable for arbitrarily given deterministic finite automata
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Any language in each category is generated by a grammar and by an automaton in the category in the same line.
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A finite language shouldn't be confused with a (usually infinite) language generated by a finite automaton.
4048: 3986: 3911: 3526: 3047:(1991). "Constructivity issues in graph algorithms". In Myers, J. Paul Jr.; O'Donnell, Michael J. (eds.). 2684: 977:. The converse is not true: for example, the language consisting of all strings having the same number of 796: 49: 3991: 3939: 3752: 2379: 1261: 998: 974: 450: 2363: 1881:, witnessing the non-regularity of the Dyck language. Care must be taken since some of the eigenvalues 3049:
Constructivity in Computer Science, Summer Symposium, San Antonio, Texas, USA, June 19-22, Proceedings
1931: 1845: 4084: 4059: 3916: 3877: 2548: 364: 3531: 1967:, but the number of words of even or odd length are of this form; the corresponding eigenvalues are 3693: 1128: 580: 505: 428: 346: 84: 1884: 4069: 4011: 3955: 3234: 1466: 1019: 1013: 1009: 470: 180: 69: 65: 985:'s is context-free but not regular. To prove that a language is not regular, one often uses the 393:
Some of the equivalences above, particularly those among the first four formalisms, are called
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J. Hartmanis, P. L. Lewis II, and R. E. Stearns. Hierarchies of memory-limited computations.
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The zeta function of a regular language is not in general rational, but that of an arbitrary
4053: 3973: 3819: 3713: 3697: 3672: 3626: 3544: 3536: 3417: 3407: 3218: 3173: 3052: 3044: 2992: 2670: 2638: 2608: 2600: 2588: 2499: 2474: 2367: 2312: 2286: 2282: 2241:{\displaystyle \zeta _{L}(z)=\exp \left({\sum _{n\geq 0}s_{L}(n){\frac {z^{n}}{n}}}\right).} 832: 816: 368: 308: 304: 76: 3230: 1318: 4016: 3931: 3898: 3814: 3787: 3783: 3676: 3630: 3548: 3421: 3226: 3040: 2674: 2642: 2612: 2592: 2503: 2296: 2281:. Likewise, the notion of a recognizable language (by a finite automaton) has namesake as 2277:
generalizes the notion (of regular/rational language) to monoids that are not necessarily
2252: 2039: 1970: 1023: 776: 263: 92: 61: 3278:
Proceedings of the 6th Annual IEEE Symposium on Switching Circuit Theory and Logic Design
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The Equivalence Problem for Regular Expressions with Squaring Requires Exponential Space
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that can be solved in constant space (the space used is independent of the input size).
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consists precisely of regular languages. For a binary alphabet, the theory is called
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with a regular language. Even more, regular languages are closed under quotients with
4130: 4112: 3412: 3395: 3202: 1742: 650:, it is decidable whether they accept the same language. As a consequence, using the 531: 3517:
Berstel, Jean; Reutenauer, Christophe (1990). "Zeta functions of formal languages".
3238: 145:) is a regular language. Due to this, the empty string language {Δ} is also regular. 2620: 2566: 2290: 2274: 418: 192: 3135:
L. J. Stockmeyer; A. R. Meyer (1973). "Word Problems Requiring Exponential Time".
1681:{\displaystyle s_{L}(n)=p_{1}(n)\lambda _{1}^{n}+\dotsb +p_{k}(n)\lambda _{k}^{n}} 3747: 3172:. Lecture Notes in Computer Science. Vol. 2500. Springer. pp. 207–230. 37:"Kleene's theorem" redirects here. For his theorems for recursive functions, see 4079: 4001: 3926: 3051:. Lecture Notes in Computer Science. Vol. 613. Springer. pp. 150–158. 2278: 1031: 961: 772: 564: 357: 142: 75:
Alternatively, a regular language can be defined as a language recognised by a
17: 2573:. Encyclopedia of Mathematics and Its Applications. Vol. 137. Cambridge: 1395: 858: 3256:(1. publ. ed.). Ithaca, NY: Association for Symbolic Logic. p. 75. 3177: 3116: 2263:
The notion of a regular language has been generalized to infinite words (see
3336: 3124:. 13th Annual IEEE Symp. on Switching and Automata Theory. pp. 125–129. 2319:. Also in this context, Kleene's theorem finds a generalization called the 3717: 1908:
could have the same magnitude. For example, the number of words of length
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A simple example of a language that is not regular is the set of strings {
3316: 315: 79:. The equivalence of regular expressions and finite automata is known as 2607:. Pure and Applied Mathematics. Vol. 58. New York: Academic Press. 775:
already for a singleton alphabet. For larger alphabets, that problem is
3611:. Progress in Theoretical Computer Science. Basel: BirkhĂ€user. p.  3469: 3222: 3078:
Hopcroft, Ullman (1979), Theorem 3.8, p.64; see also Theorem 3.10, p.67
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Eilenberg (1974), p. 16 (Example II, 2.8) and p. 25 (Example II, 5.2).
3712:. Lecture Notes in Computer Science. Vol. 1987. pp. 39–50. 2933:
Syntactic and Structural Pattern Recognition: Theory and Applications
2311:. In this algebraic context, the regular languages (corresponding to 828: 339: 245:
it is the language of a regular expression (by the above definition)
207:'s, or the language consisting of all strings of the form: several 4042: 1745:
of strings of balanced parentheses. The number of words of length
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A regular language satisfies the following equivalent properties:
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Alfred V. Aho and John E. Hopcroft and Jeffrey D. Ullman (1974).
1996:. In general, for every regular language there exists a constant 3710:
Trends, Techniques, and Problems in Theoretical Computer Science
1835:{\displaystyle C_{n}\sim {\frac {4^{n}}{n^{3/2}{\sqrt {\pi }}}}} 409:
originates from a 1951 technical report where Kleene introduced
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Formal language that can be expressed using a regular expression
3756: 3209:(1984). "Parity, circuits, and the polynomial-time hierarchy". 2814:
Handbook of Formal Languages: Volume 1. Word, Language, Grammar
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in a different meaning at first (referring to what is called
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Each category of languages, except those marked by a , is a
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in the language of all even binary words is not of the form
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Introduction to Automata Theory, Languages, and Computation
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are regular, so is the result of the following operations:
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is finite. (This number equals the number of states of the
3657:. Translated from the French by Reuben Thomas. Cambridge: 2959:
Representation of Events in Nerve Nets and Finite Automata
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Automatic Sequences: Theory, Applications, Generalizations
2484:. Cambridge Studies in Advanced Mathematics. Vol. 1. 3484:"Number of words of a given length in a regular language" 2964:(Research Memorandum). U.S. Air Force / RAND Corporation. 2299:
is another generalization, this time in the context of a
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can be proved by counting the words of a given length in
625:. Given a nondeterministic finite automaton to recognize 3069:
Hopcroft, Ullman (1979), Chapter 3, Exercise 3.4g, p. 72
1216:{\displaystyle S_{L}(z)=\sum _{n\geq 0}s_{L}(n)z^{n}\ .} 3434:
Flajolet & Sedgweick, section V.3.1, equation (13).
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4. ⇒ 2. see Hopcroft, Ullman (1979), Theorem 9.1, p.218
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2. ⇒ 4. see Hopcroft, Ullman (1979), Theorem 9.2, p.219
779:. If regular expressions are extended to allow also a 230: 72:
that allow the recognition of non-regular languages).
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Sakarovitch, J (1987). "Kleene's theorem revisited".
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Finite automata, formal logic, and circuit complexity
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Discrete Mathematics and Its Applications 7th edition
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of all regular languages is sometimes referred to as
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For regular expressions, the universality problem is
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under various operations, that is, if the languages
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All finite languages are regular; in particular the
3366:. In Jörg Flum; Erich GrÀdel; Thomas Wilke (eds.). 3087:
Aho, Hopcroft, Ullman (1974), Exercise 10.14, p.401
2315:-weighted rational expressions) are usually called 91:, regular languages are the languages generated by 3604: 3138:Proc. 5th ann. symp. on Theory of computing (STOC) 2714: 2240: 2116: 2057: 2028: 2008: 1988: 1959: 1920: 1900: 1873: 1834: 1760: 1733: 1708: 1680: 1564: 1544: 1524: 1488: 1455: 1386: 1334: 1299: 1250: 1215: 1111: 1091: 1071: 1004:Important subclasses of regular languages include 910: 553: 3096:Aho, Hopcroft, Ullman (1974), Theorem 10.14, p399 387:leads to the concept of a recognizable language. 183:for syntax and semantics of regular expressions. 2752:The Oxford Handbook of Computational Linguistics 2571:Noncommutative rational series with applications 965:Regular language in classes of Chomsky hierarchy 911:{\displaystyle \{0^{n}1^{n}:n\in \mathbb {N} \}} 3593:), the latter with two chapters by Bret Tilson. 415:"any suggestions as to a more descriptive term" 3291:"How to prove that a language is not regular?" 2930:Horst Bunke; Alberto Sanfeliu (January 1990). 2812:. In Grzegorz Rozenberg; Arto Salomaa (eds.). 2717:The Design and Analysis of Computer Algorithms 2117:{\displaystyle C_{a}m^{p_{a}}\lambda _{a}^{m}} 1238:is regular. Hence for every regular language 3768: 3115:A.R. Meyer & L.J. Stockmeyer (Oct 1972). 3105:Hopcroft, Ullman (1979), Theorem 13.15, p.351 2859:Robert Sedgewick; Kevin Daniel Wayne (2011). 2688:: Symbolic Combinatorics. Online book, 2002. 1456:{\displaystyle p_{1}(x),\,\ldots ,\,p_{k}(x)} 973:, one notices that every regular language is 929:regular, it requires a machine with at least 421:, in his 1959 seminal article, used the term 8: 3368:Logic and automata: history and perspectives 2886:Jean-Paul Allouche; Jeffrey Shallit (2003). 2865:. Addison-Wesley Professional. p. 794. 2776: 2774: 2772: 2744: 2742: 2692:John E. Hopcroft; Jeffrey D. Ullman (1979). 905: 868: 103:The collection of regular languages over an 30:For natural language that is regulated, see 4090:Counter-free (with aperiodic finite monoid) 3507:Flajolet & Sedgewick (2002) Theorem V.3 2892:. Cambridge University Press. p. 129. 2605:Automata, Languages, and Machines. Volume A 1034:: this class includes all finite languages. 941:is the input size). In other words, DSPACE( 111:The empty language Ø is a regular language. 3800: 3775: 3761: 3753: 3389: 3387: 2978:"On Certain Formal Properties of Grammars" 1691:Thus, non-regularity of certain languages 3530: 3411: 2996: 2656:Introduction to the Theory of Computation 2219: 2213: 2198: 2182: 2177: 2149: 2143: 2108: 2103: 2091: 2086: 2076: 2070: 2041: 2021: 2001: 1972: 1951: 1933: 1913: 1892: 1886: 1865: 1847: 1822: 1812: 1808: 1797: 1791: 1782: 1776: 1750: 1721: 1696: 1672: 1667: 1648: 1629: 1624: 1605: 1583: 1577: 1557: 1537: 1507: 1501: 1480: 1468: 1438: 1433: 1426: 1408: 1402: 1378: 1373: 1366: 1357: 1351: 1326: 1320: 1285: 1269: 1263: 1243: 1201: 1182: 1166: 1144: 1138: 1104: 1084: 1054: 1048: 1039:The number of words in a regular language 901: 900: 885: 875: 866: 540: 363:the number of equivalence classes of its 3154:Hopcroft, Ullman (1979), Corollary p.353 2919:. McGraw-Hill Science. pp. 873–880. 2755:. Oxford University Press. p. 754. 2682:Philippe Flajolet and Robert Sedgewick, 960: 642:Given two deterministic finite automata 3254:Logical foundations of proof complexity 2738: 2343: 994: 969:To locate the regular languages in the 651: 3982:Linear context-free rewriting language 3252:Cook, Stephen; Nguyen, Phuong (2010). 2551:for an illustration of the proof idea. 1226:The generating function of a language 369:minimal deterministic finite automaton 175:No other languages over ÎŁ are regular. 172:(concatenation) are regular languages. 3907:Linear context-free rewriting systems 3561:Berstel & Reutenauer (2011) p.222 3470:"Proof of theorem for arbitrary DFAs" 1768:in the Dyck language is equal to the 1079:denote the number of words of length 993:. Other approaches include using the 857:, because the nonregular language of 107:ÎŁ is defined recursively as follows: 7: 3643:Berstel & Reutenauer (2011) p.47 3359:Volker Diekert; Paul Gastin (2008). 3170:Automata, Logics, and Infinite Games 997:of regular languages or quantifying 383:⊆ ÎŁ. In this case, equivalence over 2301:formal power series over a semiring 4115:of the category directly above it. 1300:{\displaystyle s_{L}(n)_{n\geq 0}} 286:it can be accepted by a read-only 268:it is the language accepted by an 203:} which contain an even number of 25: 3573:Automata, languages, and machines 3541:10.1090/s0002-9947-1990-0998123-x 3361:"First-order definable languages" 2936:. World Scientific. p. 248. 2847:Lecture Notes in Computer Science 2569:; Reutenauer, Christophe (2011). 2352:Thompson's construction algorithm 957:Location in the Chomsky hierarchy 274:it is the language accepted by a 255:it is the language accepted by a 250:nondeterministic finite automaton 248:it is the language accepted by a 3012:Chomsky 1959, Footnote 10, p.150 2957:Stephen Cole Kleene (Dec 1951). 2625:Jewels of Formal Language Theory 2036:, the number of words of length 1960:{\displaystyle p(n)\lambda ^{n}} 1874:{\displaystyle p(n)\lambda ^{n}} 467:set-theoretic Boolean operations 298:BĂŒchi–Elgot–Trakhtenbrot theorem 813:computational complexity theory 130: } is a regular language. 3370:. Amsterdam University Press. 2787:. CRC Press. pp. 98–103. 2472:3. ⇔ 11. see the proof in the 2333:Induction of regular languages 2303:. This approach gives rise to 2210: 2204: 2161: 2155: 1944: 1938: 1858: 1852: 1660: 1654: 1617: 1611: 1595: 1589: 1519: 1513: 1450: 1444: 1420: 1414: 1282: 1275: 1194: 1188: 1156: 1150: 1066: 1060: 1016:of every word in the language. 621:the reverse (or mirror image) 257:deterministic finite automaton 83:(after American mathematician 1: 3653:Sakarovitch, Jacques (2009). 3166:"Decidability of S1S and S2S" 2998:10.1016/S0019-9958(59)90362-6 2321:Kleene-SchĂŒtzenberger theorem 2305:weighted rational expressions 1741:. Consider, for example, the 861:, or the nonregular language 433:today), but noticed that his 3413:10.1016/0304-3975(89)90159-x 3321:. Springer. pp. 76–77. 2543:. Deciding this property is 1901:{\displaystyle \lambda _{i}} 1121:ordinary generating function 937:) space to recognize (where 437:were equivalent to Kleene's 270:alternating finite automaton 156:are regular languages, then 46:theoretical computer science 3655:Elements of automata theory 3211:Mathematical Systems Theory 1842:, which is not of the form 1489:{\displaystyle n\geq n_{0}} 32:List of language regulators 4158: 3997:Deterministic context-free 3922:Deterministic context-free 3700:report of the same title, 3659:Cambridge University Press 3603:Straubing, Howard (1994). 3577:in two volumes "A" (1974, 2575:Cambridge University Press 2486:Cambridge University Press 2478:article, and see p.160 in 2330: 1311:; that is, there exist an 918:can both be recognized in 662:, with accepted languages 585:finite state transductions 449:The regular languages are 294:monadic second-order logic 39:Kleene's recursion theorem 36: 29: 4108: 4070:Nondeterministic pushdown 3798: 3315:Hromkovič, Juraj (2004). 3003:Here: Definition 8, p.149 2482:Algebraic automata theory 2480:Holcombe, W.M.L. (1982). 280:it can be generated by a 262:it can be generated by a 64:that can be defined by a 3178:10.1007/3-540-36387-4_12 2816:. Springer. p. 41. 1525:{\displaystyle s_{L}(n)} 1072:{\displaystyle s_{L}(n)} 787:" denoting the same as " 554:{\displaystyle K\circ L} 520:the regular operations: 435:"finite state languages" 413:and explicitly welcomed 276:two-way finite automaton 2985:Information and Control 2781:Mark V. Lawson (2003). 797:elementary substructure 638:Decidability properties 211:'s followed by several 137:is a regular language, 70:augmented with features 4075:Deterministic pushdown 3951:Recursively enumerable 3394:Honkala, Juha (1989). 2913:Kenneth Rosen (2011). 2749:Ruslan Mitkov (2003). 2685:Analytic Combinatorics 2327:Learning from examples 2242: 2118: 2059: 2030: 2010: 1990: 1961: 1922: 1902: 1875: 1836: 1762: 1735: 1710: 1682: 1566: 1546: 1526: 1490: 1457: 1388: 1336: 1301: 1252: 1217: 1113: 1093: 1073: 966: 912: 555: 50:formal language theory 3718:10.1007/3540185356_29 2976:Noam Chomsky (1959). 2627:. Pitman Publishing. 2426:Myhill–Nerode theorem 2394:is stronger than the 2380:powerset construction 2243: 2119: 2060: 2031: 2011: 1991: 1962: 1923: 1903: 1876: 1837: 1763: 1736: 1711: 1683: 1567: 1547: 1527: 1491: 1458: 1389: 1337: 1335:{\displaystyle n_{0}} 1302: 1253: 1218: 1114: 1094: 1074: 999:Kolmogorov complexity 987:Myhill–Nerode theorem 964: 945:(log log  933:(log log  913: 849:. On the other hand, 556: 405:Apparently, the term 292:it can be defined in 237:Equivalent formalisms 4060:Tree stack automaton 3519:Trans. Am. Math. Soc 3488:cs.stackexchange.com 3449:cs.stackexchange.com 3295:cs.stackexchange.com 3280:, pp. 179–190. 1965. 3164:Weyer, Mark (2002). 3144:. ACM. pp. 1–9. 3045:Langston, Michael A. 2849:2500, Springer 2002. 2549:File:RegSubsetNP.pdf 2267:) and to trees (see 2142: 2069: 2058:{\displaystyle dm+a} 2040: 2020: 2000: 1989:{\displaystyle 2,-2} 1971: 1932: 1912: 1885: 1846: 1775: 1749: 1720: 1695: 1576: 1556: 1536: 1500: 1467: 1463:such that for every 1401: 1350: 1319: 1262: 1242: 1137: 1103: 1083: 1047: 865: 539: 365:syntactic congruence 314:, meaning it is the 3968:range concatenation 3893:range concatenation 3041:Fellows, Michael R. 3030:Salomaa (1981) p.27 3021:Salomaa (1981) p.28 2810:"Regular languages" 2113: 1677: 1634: 1532:of words of length 1129:formal power series 1020:Star-free languages 629:, an automaton for 614:is regular for any 581:string homomorphism 506:relative complement 429:Chomsky normal form 347:monoid homomorphism 122:belongs to ÎŁ), the 85:Stephen Cole Kleene 3571:Samuel Eilenberg. 3400:Theor. Comput. Sci 3223:10.1007/BF01744431 3057:10.1007/BFB0021088 2721:. Addison-Wesley. 2698:. Addison-Wesley. 2659:. PWS Publishing. 2390:3. ⇒ 2. since the 2364:Kleene's algorithm 2317:rational languages 2238: 2193: 2114: 2099: 2065:is asymptotically 2055: 2026: 2016:such that for all 2006: 1986: 1957: 1918: 1898: 1871: 1832: 1761:{\displaystyle 2n} 1758: 1734:{\displaystyle L'} 1731: 1709:{\displaystyle L'} 1706: 1678: 1663: 1620: 1562: 1542: 1522: 1486: 1453: 1384: 1332: 1309:constant-recursive 1297: 1248: 1213: 1177: 1109: 1089: 1069: 1010:regular expression 995:closure properties 967: 908: 807:Complexity results 750:Membership: given 551: 445:Closure properties 181:regular expression 66:regular expression 4124: 4123: 4103: 4102: 4065:Embedded pushdown 3961:Context-sensitive 3886:Context-sensitive 3820:Abstract machines 3805:Chomsky hierarchy 3727:978-3-540-18535-2 3668:978-0-521-84425-3 3585:) and "B" (1976, 3575:. Academic Press. 3377:978-90-5356-576-6 3263:978-0-521-51729-4 3187:978-3-540-00388-5 2943:978-9971-5-0566-0 2899:978-0-521-82332-6 2872:978-0-321-57351-3 2823:978-3-540-60420-4 2808:Sheng Yu (1997). 2794:978-1-58488-255-8 2762:978-0-19-927634-9 2601:Eilenberg, Samuel 2584:978-0-521-19022-0 2392:former definition 2309:weighted automata 2228: 2178: 2029:{\displaystyle a} 2009:{\displaystyle d} 1921:{\displaystyle n} 1830: 1827: 1565:{\displaystyle L} 1545:{\displaystyle n} 1251:{\displaystyle L} 1232:rational function 1209: 1162: 1112:{\displaystyle L} 1092:{\displaystyle n} 971:Chomsky hierarchy 951:logarithmic space 925:If a language is 853:does not contain 833:decision problems 781:squaring operator 738:Universality: is 705:Disjointness: is 99:Formal definition 89:Chomsky hierarchy 58:rational language 16:(Redirected from 4149: 4137:Formal languages 4119: 4116: 4080:Visibly pushdown 4054:Thread automaton 4002:Visibly pushdown 3970: 3927:Visibly pushdown 3895: 3882:(no common name) 3801: 3788:formal languages 3777: 3770: 3763: 3754: 3731: 3698:RAND Corporation 3681: 3680: 3650: 3644: 3641: 3635: 3634: 3610: 3600: 3594: 3576: 3568: 3562: 3559: 3553: 3552: 3534: 3514: 3508: 3505: 3499: 3498: 3496: 3494: 3480: 3474: 3473: 3466: 3460: 3459: 3457: 3455: 3441: 3435: 3432: 3426: 3425: 3415: 3391: 3382: 3381: 3365: 3356: 3350: 3347: 3341: 3340: 3312: 3306: 3305: 3303: 3301: 3287: 3281: 3274: 3268: 3267: 3249: 3243: 3242: 3201:Furst, Merrick; 3198: 3192: 3191: 3161: 3155: 3152: 3146: 3145: 3143: 3132: 3126: 3125: 3123: 3112: 3106: 3103: 3097: 3094: 3088: 3085: 3079: 3076: 3070: 3067: 3061: 3060: 3037: 3031: 3028: 3022: 3019: 3013: 3010: 3004: 3002: 3000: 2982: 2973: 2967: 2965: 2963: 2954: 2948: 2947: 2927: 2921: 2920: 2910: 2904: 2903: 2883: 2877: 2876: 2856: 2850: 2843: 2837: 2834: 2828: 2827: 2805: 2799: 2798: 2778: 2767: 2766: 2746: 2732: 2720: 2709: 2678: 2646: 2616: 2596: 2552: 2547:in general; see 2514: 2508: 2507: 2475:Syntactic monoid 2470: 2464: 2434: 2428: 2424:3. ⇔ 10. by the 2422: 2416: 2413: 2407: 2404: 2398: 2388: 2382: 2376: 2370: 2360: 2354: 2348: 2283:recognizable set 2247: 2245: 2244: 2239: 2234: 2230: 2229: 2224: 2223: 2214: 2203: 2202: 2192: 2154: 2153: 2123: 2121: 2120: 2115: 2112: 2107: 2098: 2097: 2096: 2095: 2081: 2080: 2064: 2062: 2061: 2056: 2035: 2033: 2032: 2027: 2015: 2013: 2012: 2007: 1995: 1993: 1992: 1987: 1966: 1964: 1963: 1958: 1956: 1955: 1927: 1925: 1924: 1919: 1907: 1905: 1904: 1899: 1897: 1896: 1880: 1878: 1877: 1872: 1870: 1869: 1841: 1839: 1838: 1833: 1831: 1829: 1828: 1823: 1821: 1820: 1816: 1802: 1801: 1792: 1787: 1786: 1767: 1765: 1764: 1759: 1740: 1738: 1737: 1732: 1730: 1715: 1713: 1712: 1707: 1705: 1687: 1685: 1684: 1679: 1676: 1671: 1653: 1652: 1633: 1628: 1610: 1609: 1588: 1587: 1571: 1569: 1568: 1563: 1551: 1549: 1548: 1543: 1531: 1529: 1528: 1523: 1512: 1511: 1495: 1493: 1492: 1487: 1485: 1484: 1462: 1460: 1459: 1454: 1443: 1442: 1413: 1412: 1393: 1391: 1390: 1385: 1383: 1382: 1362: 1361: 1341: 1339: 1338: 1333: 1331: 1330: 1306: 1304: 1303: 1298: 1296: 1295: 1274: 1273: 1257: 1255: 1254: 1249: 1222: 1220: 1219: 1214: 1207: 1206: 1205: 1187: 1186: 1176: 1149: 1148: 1118: 1116: 1115: 1110: 1098: 1096: 1095: 1090: 1078: 1076: 1075: 1070: 1059: 1058: 917: 915: 914: 909: 904: 890: 889: 880: 879: 817:complexity class 684:Containment: is 680:, respectively: 606:is regular then 571: 562: 560: 558: 557: 552: 529: 516: 503: 494: 481: 439:"regular events" 411:"regular events" 395:Kleene's theorem 309:syntactic monoid 81:Kleene's theorem 77:finite automaton 54:regular language 21: 4157: 4156: 4152: 4151: 4150: 4148: 4147: 4146: 4142:Finite automata 4127: 4126: 4125: 4120: 4117: 4110: 4104: 4099: 4021: 3965: 3944: 3890: 3871: 3794: 3792:formal grammars 3784:Automata theory 3781: 3738: 3728: 3707: 3690: 3688:Further reading 3685: 3684: 3669: 3652: 3651: 3647: 3642: 3638: 3623: 3602: 3601: 3597: 3570: 3569: 3565: 3560: 3556: 3532:10.1.1.309.3005 3516: 3515: 3511: 3506: 3502: 3492: 3490: 3482: 3481: 3477: 3468: 3467: 3463: 3453: 3451: 3443: 3442: 3438: 3433: 3429: 3393: 3392: 3385: 3378: 3363: 3358: 3357: 3353: 3348: 3344: 3329: 3314: 3313: 3309: 3299: 3297: 3289: 3288: 3284: 3275: 3271: 3264: 3251: 3250: 3246: 3207:Sipser, Michael 3200: 3199: 3195: 3188: 3163: 3162: 3158: 3153: 3149: 3141: 3134: 3133: 3129: 3121: 3114: 3113: 3109: 3104: 3100: 3095: 3091: 3086: 3082: 3077: 3073: 3068: 3064: 3039: 3038: 3034: 3029: 3025: 3020: 3016: 3011: 3007: 2980: 2975: 2974: 2970: 2961: 2956: 2955: 2951: 2944: 2929: 2928: 2924: 2912: 2911: 2907: 2900: 2885: 2884: 2880: 2873: 2858: 2857: 2853: 2844: 2840: 2835: 2831: 2824: 2807: 2806: 2802: 2795: 2784:Finite Automata 2780: 2779: 2770: 2763: 2748: 2747: 2740: 2735: 2729: 2712: 2706: 2691: 2667: 2651:Sipser, Michael 2649: 2635: 2619: 2599: 2585: 2565: 2561: 2556: 2555: 2542: 2533: 2524: 2515: 2511: 2496: 2479: 2471: 2467: 2451:if and only if 2443:is defined as: 2435: 2431: 2423: 2419: 2414: 2410: 2405: 2401: 2389: 2385: 2378:2. ⇒ 3. by the 2377: 2373: 2361: 2357: 2349: 2345: 2340: 2335: 2329: 2297:Rational series 2261: 2259:Generalizations 2253:cyclic language 2215: 2194: 2173: 2145: 2140: 2139: 2087: 2082: 2072: 2067: 2066: 2038: 2037: 2018: 2017: 1998: 1997: 1969: 1968: 1947: 1930: 1929: 1910: 1909: 1888: 1883: 1882: 1861: 1844: 1843: 1804: 1803: 1793: 1778: 1773: 1772: 1747: 1746: 1723: 1718: 1717: 1698: 1693: 1692: 1644: 1601: 1579: 1574: 1573: 1554: 1553: 1534: 1533: 1503: 1498: 1497: 1476: 1465: 1464: 1434: 1404: 1399: 1398: 1374: 1353: 1348: 1347: 1322: 1317: 1316: 1281: 1265: 1260: 1259: 1240: 1239: 1197: 1178: 1140: 1135: 1134: 1101: 1100: 1081: 1080: 1050: 1045: 1044: 1041: 1028:complementation 1024:algebra of sets 959: 881: 871: 863: 862: 809: 777:PSPACE-complete 766: 746: 734: 722: 713: 701: 692: 679: 670: 640: 567: 537: 536: 534: 521: 508: 499: 486: 473: 447: 360:on its alphabet 307:by some finite 264:regular grammar 239: 189: 101: 93:Type-3 grammars 62:formal language 56:(also called a 42: 35: 28: 23: 22: 18:Finite language 15: 12: 11: 5: 4155: 4153: 4145: 4144: 4139: 4129: 4128: 4122: 4121: 4109: 4106: 4105: 4101: 4100: 4098: 4097: 4095:Acyclic finite 4092: 4087: 4082: 4077: 4072: 4067: 4062: 4056: 4051: 4046: 4045:Turing Machine 4040: 4038:Linear-bounded 4035: 4030: 4028:Turing machine 4024: 4022: 4020: 4019: 4014: 4009: 4004: 3999: 3994: 3989: 3987:Tree-adjoining 3984: 3979: 3976: 3971: 3963: 3958: 3953: 3947: 3945: 3943: 3942: 3937: 3934: 3929: 3924: 3919: 3914: 3912:Tree-adjoining 3909: 3904: 3901: 3896: 3888: 3883: 3880: 3874: 3872: 3870: 3869: 3866: 3863: 3860: 3857: 3854: 3851: 3848: 3845: 3842: 3839: 3836: 3833: 3830: 3826: 3823: 3822: 3817: 3812: 3807: 3799: 3796: 3795: 3782: 3780: 3779: 3772: 3765: 3757: 3751: 3750: 3743:Complexity Zoo 3737: 3736:External links 3734: 3733: 3732: 3726: 3705: 3689: 3686: 3683: 3682: 3667: 3661:. p. 86. 3645: 3636: 3621: 3595: 3563: 3554: 3525:(2): 533–546. 3509: 3500: 3475: 3461: 3436: 3427: 3406:(3): 341–347. 3383: 3376: 3351: 3342: 3327: 3307: 3282: 3269: 3262: 3244: 3203:Saxe, James B. 3193: 3186: 3156: 3147: 3127: 3107: 3098: 3089: 3080: 3071: 3062: 3032: 3023: 3014: 3005: 2991:(2): 137–167. 2968: 2949: 2942: 2922: 2905: 2898: 2878: 2871: 2851: 2838: 2829: 2822: 2800: 2793: 2768: 2761: 2737: 2736: 2734: 2733: 2727: 2710: 2704: 2689: 2680: 2665: 2647: 2633: 2617: 2597: 2583: 2562: 2560: 2557: 2554: 2553: 2538: 2529: 2520: 2509: 2494: 2465: 2429: 2417: 2408: 2399: 2383: 2371: 2355: 2342: 2341: 2339: 2336: 2331:Main article: 2328: 2325: 2269:tree automaton 2260: 2257: 2249: 2248: 2237: 2233: 2227: 2222: 2218: 2212: 2209: 2206: 2201: 2197: 2191: 2188: 2185: 2181: 2176: 2172: 2169: 2166: 2163: 2160: 2157: 2152: 2148: 2131:of a language 2111: 2106: 2102: 2094: 2090: 2085: 2079: 2075: 2054: 2051: 2048: 2045: 2025: 2005: 1985: 1982: 1979: 1976: 1954: 1950: 1946: 1943: 1940: 1937: 1917: 1895: 1891: 1868: 1864: 1860: 1857: 1854: 1851: 1826: 1819: 1815: 1811: 1807: 1800: 1796: 1790: 1785: 1781: 1770:Catalan number 1757: 1754: 1729: 1726: 1704: 1701: 1675: 1670: 1666: 1662: 1659: 1656: 1651: 1647: 1643: 1640: 1637: 1632: 1627: 1623: 1619: 1616: 1613: 1608: 1604: 1600: 1597: 1594: 1591: 1586: 1582: 1561: 1541: 1521: 1518: 1515: 1510: 1506: 1483: 1479: 1475: 1472: 1452: 1449: 1446: 1441: 1437: 1432: 1429: 1425: 1422: 1419: 1416: 1411: 1407: 1381: 1377: 1372: 1369: 1365: 1360: 1356: 1329: 1325: 1294: 1291: 1288: 1284: 1280: 1277: 1272: 1268: 1247: 1224: 1223: 1212: 1204: 1200: 1196: 1193: 1190: 1185: 1181: 1175: 1172: 1169: 1165: 1161: 1158: 1155: 1152: 1147: 1143: 1108: 1088: 1068: 1065: 1062: 1057: 1053: 1040: 1037: 1036: 1035: 1017: 958: 955: 907: 903: 899: 896: 893: 888: 884: 878: 874: 870: 808: 805: 769: 768: 762: 748: 742: 736: 730: 726:Emptiness: is 724: 718: 709: 703: 697: 688: 675: 666: 639: 636: 635: 634: 619: 602:languages: If 573: 550: 547: 544: 518: 446: 443: 377: 376: 361: 334:} of a subset 301: 290: 288:Turing machine 284: 282:prefix grammar 278: 272: 266: 260: 253: 246: 238: 235: 188: 185: 177: 176: 173: 146: 131: 112: 100: 97: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 4154: 4143: 4140: 4138: 4135: 4134: 4132: 4114: 4113:proper subset 4107: 4096: 4093: 4091: 4088: 4086: 4083: 4081: 4078: 4076: 4073: 4071: 4068: 4066: 4063: 4061: 4057: 4055: 4052: 4050: 4047: 4044: 4041: 4039: 4036: 4034: 4031: 4029: 4026: 4025: 4023: 4018: 4015: 4013: 4010: 4008: 4005: 4003: 4000: 3998: 3995: 3993: 3990: 3988: 3985: 3983: 3980: 3977: 3975: 3972: 3969: 3964: 3962: 3959: 3957: 3954: 3952: 3949: 3948: 3946: 3941: 3940:Non-recursive 3938: 3935: 3933: 3930: 3928: 3925: 3923: 3920: 3918: 3915: 3913: 3910: 3908: 3905: 3902: 3900: 3897: 3894: 3889: 3887: 3884: 3881: 3879: 3876: 3875: 3873: 3867: 3864: 3861: 3858: 3855: 3852: 3849: 3846: 3843: 3840: 3837: 3834: 3831: 3828: 3827: 3825: 3824: 3821: 3818: 3816: 3813: 3811: 3808: 3806: 3803: 3802: 3797: 3793: 3789: 3785: 3778: 3773: 3771: 3766: 3764: 3759: 3758: 3755: 3749: 3745: 3744: 3740: 3739: 3735: 3729: 3723: 3719: 3715: 3711: 3706: 3703: 3699: 3695: 3692: 3691: 3687: 3678: 3674: 3670: 3664: 3660: 3656: 3649: 3646: 3640: 3637: 3632: 3628: 3624: 3622:3-7643-3719-2 3618: 3614: 3609: 3608: 3599: 3596: 3592: 3591:9780080873756 3588: 3584: 3583:9780080873749 3580: 3574: 3567: 3564: 3558: 3555: 3550: 3546: 3542: 3538: 3533: 3528: 3524: 3520: 3513: 3510: 3504: 3501: 3489: 3485: 3479: 3476: 3471: 3465: 3462: 3450: 3446: 3440: 3437: 3431: 3428: 3423: 3419: 3414: 3409: 3405: 3401: 3397: 3390: 3388: 3384: 3379: 3373: 3369: 3362: 3355: 3352: 3346: 3343: 3338: 3334: 3330: 3328:3-540-14015-8 3324: 3320: 3319: 3311: 3308: 3296: 3292: 3286: 3283: 3279: 3273: 3270: 3265: 3259: 3255: 3248: 3245: 3240: 3236: 3232: 3228: 3224: 3220: 3216: 3212: 3208: 3204: 3197: 3194: 3189: 3183: 3179: 3175: 3171: 3167: 3160: 3157: 3151: 3148: 3140: 3139: 3131: 3128: 3120: 3119: 3111: 3108: 3102: 3099: 3093: 3090: 3084: 3081: 3075: 3072: 3066: 3063: 3058: 3054: 3050: 3046: 3042: 3036: 3033: 3027: 3024: 3018: 3015: 3009: 3006: 2999: 2994: 2990: 2986: 2979: 2972: 2969: 2960: 2953: 2950: 2945: 2939: 2935: 2934: 2926: 2923: 2918: 2917: 2909: 2906: 2901: 2895: 2891: 2890: 2882: 2879: 2874: 2868: 2864: 2863: 2855: 2852: 2848: 2842: 2839: 2833: 2830: 2825: 2819: 2815: 2811: 2804: 2801: 2796: 2790: 2786: 2785: 2777: 2775: 2773: 2769: 2764: 2758: 2754: 2753: 2745: 2743: 2739: 2730: 2728:9780201000290 2724: 2719: 2718: 2711: 2707: 2705:0-201-02988-X 2701: 2697: 2696: 2690: 2687: 2686: 2681: 2676: 2672: 2668: 2666:0-534-94728-X 2662: 2658: 2657: 2652: 2648: 2644: 2640: 2636: 2634:0-273-08522-0 2630: 2626: 2622: 2621:Salomaa, Arto 2618: 2614: 2610: 2606: 2602: 2598: 2594: 2590: 2586: 2580: 2576: 2572: 2568: 2567:Berstel, Jean 2564: 2563: 2558: 2550: 2546: 2541: 2537: 2532: 2528: 2523: 2519: 2513: 2510: 2505: 2501: 2497: 2495:0-521-60492-3 2491: 2487: 2483: 2477: 2476: 2469: 2466: 2462: 2458: 2454: 2450: 2446: 2442: 2438: 2433: 2430: 2427: 2421: 2418: 2412: 2409: 2403: 2400: 2397: 2393: 2387: 2384: 2381: 2375: 2372: 2369: 2368:Arden's lemma 2365: 2359: 2356: 2353: 2347: 2344: 2337: 2334: 2326: 2324: 2322: 2318: 2314: 2310: 2306: 2302: 2298: 2294: 2292: 2288: 2284: 2280: 2276: 2272: 2270: 2266: 2258: 2256: 2254: 2235: 2231: 2225: 2220: 2216: 2207: 2199: 2195: 2189: 2186: 2183: 2179: 2174: 2170: 2167: 2164: 2158: 2150: 2146: 2138: 2137: 2136: 2134: 2130: 2129:zeta function 2125: 2109: 2104: 2100: 2092: 2088: 2083: 2077: 2073: 2052: 2049: 2046: 2043: 2023: 2003: 1983: 1980: 1977: 1974: 1952: 1948: 1941: 1935: 1915: 1893: 1889: 1866: 1862: 1855: 1849: 1824: 1817: 1813: 1809: 1805: 1798: 1794: 1788: 1783: 1779: 1771: 1755: 1752: 1744: 1743:Dyck language 1727: 1724: 1702: 1699: 1689: 1673: 1668: 1664: 1657: 1649: 1645: 1641: 1638: 1635: 1630: 1625: 1621: 1614: 1606: 1602: 1598: 1592: 1584: 1580: 1559: 1539: 1516: 1508: 1504: 1481: 1477: 1473: 1470: 1447: 1439: 1435: 1430: 1427: 1423: 1417: 1409: 1405: 1397: 1379: 1375: 1370: 1367: 1363: 1358: 1354: 1345: 1327: 1323: 1314: 1310: 1292: 1289: 1286: 1278: 1270: 1266: 1258:the sequence 1245: 1237: 1233: 1229: 1210: 1202: 1198: 1191: 1183: 1179: 1173: 1170: 1167: 1163: 1159: 1153: 1145: 1141: 1133: 1132: 1131: 1130: 1126: 1122: 1106: 1086: 1063: 1055: 1051: 1038: 1033: 1029: 1025: 1021: 1018: 1015: 1011: 1007: 1006: 1005: 1002: 1000: 996: 992: 991:pumping lemma 988: 984: 980: 976: 972: 963: 956: 954: 952: 948: 944: 940: 936: 932: 928: 923: 921: 897: 894: 891: 886: 882: 876: 872: 860: 856: 852: 848: 844: 843: 838: 834: 830: 826: 822: 818: 814: 806: 804: 802: 798: 792: 790: 786: 782: 778: 774: 765: 761: 757: 753: 749: 745: 741: 737: 733: 729: 725: 721: 717: 712: 708: 704: 700: 696: 691: 687: 683: 682: 681: 678: 674: 669: 665: 661: 657: 653: 649: 645: 637: 632: 628: 624: 620: 617: 613: 609: 605: 601: 597: 593: 590: 586: 582: 578: 574: 570: 566: 548: 545: 542: 533: 532:concatenation 528: 524: 519: 515: 511: 507: 504:, hence also 502: 498: 493: 489: 485: 480: 476: 472: 468: 464: 463: 462: 460: 456: 452: 444: 442: 440: 436: 432: 430: 424: 420: 416: 412: 408: 403: 401: 396: 391: 388: 386: 382: 374: 370: 366: 362: 359: 355: 351: 348: 344: 341: 337: 333: 329: 325: 321: 317: 313: 310: 306: 302: 299: 295: 291: 289: 285: 283: 279: 277: 273: 271: 267: 265: 261: 258: 254: 251: 247: 244: 243: 242: 236: 234: 232: 228: 224: 221: 216: 214: 210: 206: 202: 198: 194: 186: 184: 182: 174: 171: 167: 163: 159: 155: 151: 147: 144: 140: 136: 132: 129: 125: 121: 117: 113: 110: 109: 108: 106: 98: 96: 94: 90: 86: 82: 78: 73: 71: 67: 63: 59: 55: 51: 47: 40: 33: 19: 4049:Nested stack 4006: 3992:Context-free 3917:Context-free 3878:Unrestricted 3741: 3709: 3694:Kleene, S.C. 3654: 3648: 3639: 3606: 3598: 3572: 3566: 3557: 3522: 3518: 3512: 3503: 3491:. Retrieved 3487: 3478: 3464: 3452:. Retrieved 3448: 3439: 3430: 3403: 3399: 3367: 3354: 3345: 3317: 3310: 3298:. Retrieved 3294: 3285: 3277: 3272: 3253: 3247: 3217:(1): 13–27. 3214: 3210: 3196: 3169: 3159: 3150: 3137: 3130: 3117: 3110: 3101: 3092: 3083: 3074: 3065: 3048: 3035: 3026: 3017: 3008: 2988: 2984: 2971: 2952: 2932: 2925: 2915: 2908: 2888: 2881: 2861: 2854: 2841: 2832: 2813: 2803: 2783: 2751: 2716: 2694: 2683: 2655: 2624: 2604: 2570: 2539: 2535: 2530: 2526: 2521: 2517: 2512: 2481: 2473: 2468: 2460: 2456: 2452: 2448: 2444: 2440: 2436: 2432: 2420: 2411: 2402: 2386: 2374: 2358: 2346: 2316: 2295: 2291:power series 2275:Rational set 2273: 2262: 2250: 2132: 2128: 2126: 1690: 1394:and complex 1235: 1227: 1225: 1124: 1042: 1030:but not the 1026:) including 1012:that is the 1003: 982: 978: 975:context-free 968: 946: 938: 934: 926: 924: 919: 854: 850: 846: 841: 836: 831:(O(1)), the 824: 820: 810: 793: 788: 784: 780: 770: 763: 759: 755: 751: 743: 739: 731: 727: 719: 715: 710: 706: 698: 694: 689: 685: 676: 672: 667: 663: 659: 655: 647: 643: 641: 630: 626: 622: 615: 611: 607: 603: 599: 595: 591: 579:operations: 568: 526: 522: 513: 509: 500: 491: 487: 484:intersection 478: 474: 458: 454: 448: 438: 434: 426: 422: 419:Noam Chomsky 414: 410: 406: 404: 399: 394: 392: 389: 384: 380: 378: 372: 353: 349: 342: 338:of a finite 335: 331: 327: 323: 319: 311: 240: 226: 222: 219: 217: 212: 208: 204: 200: 196: 193:empty string 190: 178: 169: 165: 164:(union) and 161: 157: 153: 149: 138: 134: 127: 119: 115: 102: 80: 74: 57: 53: 43: 4058:restricted 2362:2. ⇒ 1. by 2350:1. ⇒ 2. by 1496:the number 1396:polynomials 1032:Kleene star 859:palindromes 827:and equals 773:NP-complete 735:= {} ? 723:= {} ? 565:Kleene star 358:free monoid 143:Kleene star 4131:Categories 3677:1188.68177 3631:0816.68086 3549:0797.68092 3422:0675.68034 2966:Here: p.46 2862:Algorithms 2675:1169.68300 2643:0487.68064 2613:0317.94045 2593:1250.68007 2559:References 2504:0489.68046 2265:ω-automata 1346:constants 747:= ÎŁ ? 497:complement 371:accepting 305:recognized 126:language { 87:). 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Index

Finite language
List of language regulators
Kleene's recursion theorem
theoretical computer science
formal language theory
formal language
regular expression
augmented with features
finite automaton
Stephen Cole Kleene
Chomsky hierarchy
Type-3 grammars
alphabet
singleton
Kleene star
regular expression
empty string
below
nondeterministic finite automaton
deterministic finite automaton
regular grammar
alternating finite automaton
two-way finite automaton
prefix grammar
Turing machine
monadic second-order logic
BĂŒchi–Elgot–Trakhtenbrot theorem
recognized
syntactic monoid
preimage

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