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Page 5099 of Mathematical Reviews Vol. , Issue 93i [page]

1993 Mathematical Reviews  
The au- thors compare the complexities of descriptions of context-free languages by context-free grammars and various types of cooper- ating/distributed grammar systems.  ...  shuffle, union, concatenation, Kleene star, and intersection over a finite alphabet.  ... 

A Complete Refinement Procedure for Regular Separability of Context-Free Languages [article]

Graeme Gange, Jorge A. Navas, Peter Schachte, Harald Sondergaard, Peter J. Stuckey
2014 arXiv   pre-print
Often, when analyzing the behaviour of systems modelled as context-free languages, we wish to know if two languages overlap.  ...  To this end, we present an effective semi-decision procedure for regular separability of context-free languages, based on counter-example guided abstraction refinement.  ...  Acknowledgments We wish to thank Georgel Calin for providing the test programs and the implementation of lcegar. We also thank Pierre Ganty for fruitful discussions about this topic.  ... 
arXiv:1411.5131v1 fatcat:o343sftukjgfndiusyutij66pm

Finite turns and the regular closure of linear context-free languages

Martin Kutrib, Andreas Malcher
2007 Discrete Applied Mathematics  
Their relationships with closures of the linear context-free languages under regular operations are studied.  ...  The regular closure of the linear languages share the strong closure properties of the context-free languages, i.e., the family is a full AFL.  ...  Since deterministic context-free languages are not closed under the regular operations union, concatenation, and Kleene star, the regular closure of the deterministic context-free languages increases the  ... 
doi:10.1016/j.dam.2007.05.021 fatcat:fpkkcniuu5arvcddg5yc2ahg7y

A complete refinement procedure for regular separability of context-free languages

Graeme Gange, Jorge A. Navas, Peter Schachte, Harald Søndergaard, Peter J. Stuckey
2016 Theoretical Computer Science  
To this end, we present a class of semi-decision procedures for regular separability of context-free languages, based on counter-example guided abstraction refinement.  ...  Often, when analyzing the behaviour of systems modelled as context-free languages, we wish to know if two languages overlap.  ...  We also wish to thank Georgel Calin for providing the test programs and the implementation of lcegar.  ... 
doi:10.1016/j.tcs.2016.01.026 fatcat:ydq4pailzzbllgc4oac2knrhia

Recognition and learning of a class of context-sensitive languages described by augmented regular expressions

René Alquézar, Alberto Sanfeliu
1997 Pattern Recognition  
In this paper, a new formalism that permits to represent a non-trivial class of context-sensitive languages, the Augmented Regular Expressions (AREs), is introduced.  ...  AREs augment the expressive power of Regular Expressions (REs) by including a set of constraints that involve the number of instances in a string of the operands of the star operations of an RE.  ...  For example, the language of rectangles L(/?l) and the context-free language { 0v~ IV20V~ I v2 = Vl + v3} cannot be described by any pattern language.  ... 
doi:10.1016/s0031-3203(96)00056-8 fatcat:kbmwatrkxzdprojglmhwqnhppy

Substitution expressions

I.P. McWhirter
1971 Journal of computer and system sciences (Print)  
This paper describes a characterization of context-free languages by means of expressions using union, substitution, and an iterative substitution called substitution star.  ...  The well-known eases of linear and regular subfamilies of context-free languages are obtainable from the general model by placing proper restrictions on the basis over which the substitution expressions  ...  Brzozowski for his guidance in the writing of this paper, and to thank the referee for many helpful comments, regarding both the style and technical content of this paper.  ... 
doi:10.1016/s0022-0000(71)80020-x fatcat:77dtptwrcfhzldnqjmbwa33ux4

Parsing with derivatives

Matthew Might, David Darais, Daniel Spiewak
2011 Proceeding of the 16th ACM SIGPLAN international conference on Functional programming - ICFP '11  
We equip the functional programmer with two equational theories that, when combined, make for an abbreviated understanding and implementation of a system for parsing context-free languages.  ...  If we consider context-free grammars as recursive regular expressions, Brzozowski's equational theory extends without modification to context-free grammars (and it generalizes to parser combinators).  ...  Acknowledgements We are grateful for the thousands of comments on reddit, hackernews, Lambda the Ultimate and elsewhere that thoroughly dissected and improved an earlier draft of this work.  ... 
doi:10.1145/2034773.2034801 dblp:conf/icfp/MightDS11 fatcat:af4guch6lbf2lpc3gdnexduyxy

Parsing with derivatives

Matthew Might, David Darais, Daniel Spiewak
2011 SIGPLAN notices  
We equip the functional programmer with two equational theories that, when combined, make for an abbreviated understanding and implementation of a system for parsing context-free languages.  ...  If we consider context-free grammars as recursive regular expressions, Brzozowski's equational theory extends without modification to context-free grammars (and it generalizes to parser combinators).  ...  Acknowledgements We are grateful for the thousands of comments on reddit, hackernews, Lambda the Ultimate and elsewhere that thoroughly dissected and improved an earlier draft of this work.  ... 
doi:10.1145/2034574.2034801 fatcat:ck2l65mrffccxetjjjrjpvnjzq

Page 5264 of Mathematical Reviews Vol. , Issue 98H [page]

1998 Mathematical Reviews  
Esik and I were working on the description of the free Conway theories.  ...  Introduction: “Star-free languages form an important subclass of regular languages: they are the ones that can be obtained from the singleton languages by a finite number of applications of the op- erations  ... 

Operational State Complexity under Parikh Equivalence [chapter]

Giovanna J. Lavado, Giovanni Pighizzini, Shinnosuke Seki
2014 Lecture Notes in Computer Science  
For union, concatenation, Kleene star, complement, intersection, shuffle, and reversal, we obtain a polynomial state complexity over any fixed alphabet, in contrast to the intrinsic exponential state complexity  ...  of the Parikh images of the languages accepted by A and B.  ...  Unlike union or intersection, both concatenation and star are known to cost an exponential number of states on dfas.  ... 
doi:10.1007/978-3-319-09704-6_26 fatcat:erydydok3jdllckaqg6mrqao7m

A Survey on Operational State Complexity [article]

Yuan Gao and Nelma Moreira and Rogério Reis and Sheng Yu
2015 arXiv   pre-print
In this survey, we review the state complexities of individual regularity preserving language operations on regular and some subregular languages.  ...  Descriptional complexity is the study of the conciseness of the various models representing formal languages.  ...  Table 14 : 14 State complexity of basic regular operations on star-free regular and unary languages, where • ∈ {∪, ∩, \, ⊕}. For non-unary star-free languages and n = 2, m ≥ 2.  ... 
arXiv:1509.03254v1 fatcat:oxleg7kkvvezxoqgscdnlghzvu

Page 3634 of Mathematical Reviews Vol. , Issue 85h [page]

1985 Mathematical Reviews  
is decidable for a regular language L and a pure context-free grammar G, it is decidable whether a given regular language is pure context-free.  ...  The paper under review shows that a special subclass of context-free language, the input-driven languages, can be recog- nized on log n-tape.  ... 

Context-Free Path Queries on RDF Graphs [article]

Xiaowang Zhang, Zhiyong Feng, Xin Wang, Guozheng Rao, Wenrui Wu
2016 arXiv   pre-print
To overcome this limitation, in this paper, we present cfSPARQL, an extension of SPARQL query language equipped with context-free grammars.  ...  Most of the navigational query languages used in the RDF community, e.g. property paths in W3C SPARQL 1.1 and nested regular expressions in nSPARQL, are based on the regular expressions.  ...  This work is supported by the program of the National Key Research and Development Program of China (2016YFB1000603) and the National Natural Science Foundation of China (NSFC) (61502336, 61373035).  ... 
arXiv:1506.00743v3 fatcat:jor6wnudqjcpfom5zitpcppbey

OPEN PROBLEMS ON REGULAR LANGUAGES: A HISTORICAL PERSPECTIVE

LAURA CHAUBARD, JEAN-ÉRIC PIN
2007 Semigroups and Formal Languages  
On the algebraic side, we present Eilenberg's variety theory and its successive improvements, including the recent notion of C-variety.  ...  We consider successively the star-height problem, the Straubing-Thérien's concatenation hierarchy and the shuffle operation.  ...  In our context, a positive Boolean algebra will be a class of languages closed under finite union and finite intersection.  ... 
doi:10.1142/9789812708700_0004 fatcat:4nq3saewxvclho2rwkfuempmxy

A Quantum Query Complexity Trichotomy for Regular Languages [article]

Scott Aaronson, Daniel Grier, Luke Schaeffer
2019 arXiv   pre-print
This is in contrast to even the context-free languages, which we show can have query complexity Theta(n^c) for all computable c in [1/2,1].  ...  The heart of the classification theorem is an explicit quantum algorithm which decides membership in any star-free language in ~O(sqrt n) time.  ...  Acknowledgements We thank Andris Ambainis, Shalev Ben-David, Robin Kothari, Han-Hsuan Lin, and Ronald de Wolf for useful discussions.  ... 
arXiv:1812.04219v3 fatcat:zo3oe6f64bfgrmhqsvxu3m4qqy
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