## Abstract

Brüggemann-Klein and Wood have introduced a new family of regular languages, the one-unambiguous regular languages, a very important notion in XML DTDs. A regular language L is one-unambiguous if and only if there exists a regular expression E over the operators of sum, catenation and Kleene star such that L(E)∈=∈L and the position automaton of E is deterministic. It implies that for a one-unambiguous expression, there exists an equivalent linear-size deterministic recognizer. In this paper, we extend the notion of one-unambiguity to weak one-unambiguity over regular expressions using the complement operator ¬. We show that a DFA with at most (n∈+∈2) states can be computed from a weakly one-unambiguous expression and that it is decidable whether or not a given DFA recognizes a weakly one-unambiguous language.

Original language | English |
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Title of host publication | Developments in Language Theory - 15th International Conference, DLT 2011, Proceedings |

Pages | 129-140 |

Number of pages | 12 |

DOIs | |

Publication status | Published - 2011 |

Event | 15th International Conference on Developments in Language Theory, DLT 2011 - Milan, Italy Duration: 2011 Jul 19 → 2011 Jul 22 |

### Publication series

Name | Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) |
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Volume | 6795 LNCS |

ISSN (Print) | 0302-9743 |

ISSN (Electronic) | 1611-3349 |

### Other

Other | 15th International Conference on Developments in Language Theory, DLT 2011 |
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Country | Italy |

City | Milan |

Period | 11/7/19 → 11/7/22 |

### Bibliographical note

Funding Information:Han was supported by the Basic Science Research Program through NRF funded by MEST (2010-0009168).

Funding Information:

★ Han was supported by the Basic Science Research Program through NRF funded by MEST (2010-0009168).

## All Science Journal Classification (ASJC) codes

- Theoretical Computer Science
- Computer Science(all)