Consensual languages and matching finite-state computations

Stefano Crespi Reghizzi; Pierluigi San Pietro

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications (2011)

  • Volume: 45, Issue: 1, page 77-97
  • ISSN: 0988-3754

Abstract

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An ever present, common sense idea in language modelling research is that, for a word to be a valid phrase, it should comply with multiple constraints at once. A new language definition model is studied, based on agreement or consensus between similar strings. Considering a regular set of strings over a bipartite alphabet made by pairs of unmarked/marked symbols, a match relation is introduced, in order to specify when such strings agree. Then a regular set over the bipartite alphabet can be interpreted as specifying another language over the unmarked alphabet, called the consensual language. A word is in the consensual language if a set of corresponding matching strings is in the original language. The family thus defined includes the regular languages and also interesting non-semilinear ones. The word problem can be solved in NLOGSPACE, hence in P time. The emptiness problem is undecidable. Closure properties are proved for intersection with regular sets and inverse alphabetical homomorphism. Several conditions for a consensual definition to yield a regular language are presented, and it is shown that the size of a consensual specification of regular languages can be in a logarithmic ratio with respect to a DFA. The family is incomparable with context-free and tree-adjoining grammar families.

How to cite

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Crespi Reghizzi, Stefano, and San Pietro, Pierluigi. "Consensual languages and matching finite-state computations." RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications 45.1 (2011): 77-97. <http://eudml.org/doc/272992>.

@article{CrespiReghizzi2011,
abstract = {An ever present, common sense idea in language modelling research is that, for a word to be a valid phrase, it should comply with multiple constraints at once. A new language definition model is studied, based on agreement or consensus between similar strings. Considering a regular set of strings over a bipartite alphabet made by pairs of unmarked/marked symbols, a match relation is introduced, in order to specify when such strings agree. Then a regular set over the bipartite alphabet can be interpreted as specifying another language over the unmarked alphabet, called the consensual language. A word is in the consensual language if a set of corresponding matching strings is in the original language. The family thus defined includes the regular languages and also interesting non-semilinear ones. The word problem can be solved in NLOGSPACE, hence in P time. The emptiness problem is undecidable. Closure properties are proved for intersection with regular sets and inverse alphabetical homomorphism. Several conditions for a consensual definition to yield a regular language are presented, and it is shown that the size of a consensual specification of regular languages can be in a logarithmic ratio with respect to a DFA. The family is incomparable with context-free and tree-adjoining grammar families.},
author = {Crespi Reghizzi, Stefano, San Pietro, Pierluigi},
journal = {RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications},
keywords = {formal languages; finite automata; consensual languages; counter machines; polynomial time parsing; non-semilinear languages; Parikh mapping; descriptive complexity of regular languages; degree of grammaticality},
language = {eng},
number = {1},
pages = {77-97},
publisher = {EDP-Sciences},
title = {Consensual languages and matching finite-state computations},
url = {http://eudml.org/doc/272992},
volume = {45},
year = {2011},
}

TY - JOUR
AU - Crespi Reghizzi, Stefano
AU - San Pietro, Pierluigi
TI - Consensual languages and matching finite-state computations
JO - RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications
PY - 2011
PB - EDP-Sciences
VL - 45
IS - 1
SP - 77
EP - 97
AB - An ever present, common sense idea in language modelling research is that, for a word to be a valid phrase, it should comply with multiple constraints at once. A new language definition model is studied, based on agreement or consensus between similar strings. Considering a regular set of strings over a bipartite alphabet made by pairs of unmarked/marked symbols, a match relation is introduced, in order to specify when such strings agree. Then a regular set over the bipartite alphabet can be interpreted as specifying another language over the unmarked alphabet, called the consensual language. A word is in the consensual language if a set of corresponding matching strings is in the original language. The family thus defined includes the regular languages and also interesting non-semilinear ones. The word problem can be solved in NLOGSPACE, hence in P time. The emptiness problem is undecidable. Closure properties are proved for intersection with regular sets and inverse alphabetical homomorphism. Several conditions for a consensual definition to yield a regular language are presented, and it is shown that the size of a consensual specification of regular languages can be in a logarithmic ratio with respect to a DFA. The family is incomparable with context-free and tree-adjoining grammar families.
LA - eng
KW - formal languages; finite automata; consensual languages; counter machines; polynomial time parsing; non-semilinear languages; Parikh mapping; descriptive complexity of regular languages; degree of grammaticality
UR - http://eudml.org/doc/272992
ER -

References

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  3. [3] S. Crespi Reghizzi and P. San Pietro, Languages defined by consensual computations. in ICTCS09 (2009). Zbl1219.68112
  4. [4] M. Jantzen, On the hierarchy of Petri net languages. ITA 13 (1979). Zbl0404.68076MR525455
  5. [5] A. Joshi and Y. Schabes, Tree-adjoining grammars, in Handbook of Formal Languages, Vol. 3, G. Rozenberg and A. Salomaa, Eds. Springer, Berlin, New York (1997), 69–124. MR1470019
  6. [6] M. Minsky, Computation: Finite and Infinite Machines. Prentice-Hall, Englewood Cliffs (1976). Zbl0195.02402MR356580
  7. [7] A. Salomaa, Theory of Automata. Pergamon Press, Oxford (1969). Zbl0193.32901MR262021
  8. [8] K. Vijay-Shanker and D.J. Weir, The equivalence of four extensions of context-free grammars. Math. Syst. Theor.27 (1994) 511–546. Zbl0813.68129MR1288685

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