### Abstract

The nondeterministic lower space bound √n of Hunt, for the problem if a regular expression with intersection describes a non-empty language, is improved to the upper bound n. For the general inequivalence problem for regular expressions with intersection the lower bound c^{n} matches the upper bound except for the constant c. And the proof for this tight lower bound is simpler than the proofs for previous bounds. Methods developed in a result about one letter alphabets are extended to get a complete characterization for the problem of deciding if one input-expression describes a given language. The complexity depends only on the property of the given language to be finite, infinite but bounded, or unbounded.

Original language | English (US) |
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Title of host publication | Automata, Languages and Programming - 7th Colloquium |

Editors | Jaco de Bakker, Jan van Leeuwen |

Publisher | Springer Verlag |

Pages | 234-245 |

Number of pages | 12 |

ISBN (Print) | 9783540100034 |

DOIs | |

Publication status | Published - Jan 1 1980 |

Event | 7th International Colloquium on Automata, Languages and Programming, ICALP 1980 - Noordwijkerhout, Netherlands Duration: Jul 14 1980 → Jul 18 1980 |

### 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 | 85 LNCS |

ISSN (Print) | 0302-9743 |

ISSN (Electronic) | 1611-3349 |

### Other

Other | 7th International Colloquium on Automata, Languages and Programming, ICALP 1980 |
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Country | Netherlands |

City | Noordwijkerhout |

Period | 7/14/80 → 7/18/80 |

### Fingerprint

### All Science Journal Classification (ASJC) codes

- Theoretical Computer Science
- Computer Science(all)

### Cite this

*Automata, Languages and Programming - 7th Colloquium*(pp. 234-245). (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics); Vol. 85 LNCS). Springer Verlag. https://doi.org/10.1007/3-540-10003-2_74