### Abstract

This paper concerns a subclass of context-free languages, called pure context-free languages, which is generated by context-free grammar with only one type of symbol (i.e., terminals and nonterminals are not distinguished), and investigates the problem of identifying from positive data a restricted class of monogenic pure context-free languages (mono-PCF languages, in short). The class of mono-PCF languages is incomparable to the class of regular languages. We show that the class of mono-PCF languages is polynomial time identifiable from positive data. That is, there is an algorithm that, given a mono- PCF language L, identifies from positive data, a grammar generating L, called a monogenic pure context-free grammar (mono-PCF grammar) satisfying the property that the time for updating a conjecture is bounded by O(N^{3}), where N is the sum of lengths of all positive data provided. This is in contrast with another result in this paper that the class of PCF languages is not identifiable in the limit from positive data.

Original language | English |
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Title of host publication | Algorithmic Learning Theory - 4th International Workshop on Analogical and Inductive Inference, AII 1994 and 5th International Workshop on Algorithmic Learning Theory, ALT 1994, Proceedings |

Editors | Setsuo Arikawa, Klaus P. Jantke |

Publisher | Springer Verlag |

Pages | 560-573 |

Number of pages | 14 |

ISBN (Print) | 9783540585206 |

Publication status | Published - 1994 Jan 1 |

Event | 4th International Workshop on Analogical and Inductive Inference, AII 1994 and 5th International Workshop on Algorithmic Learning Theory, ALT 1994 - Reinhardsbrunn Castle, Germany Duration: 1994 Oct 10 → 1994 Oct 15 |

### 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 | 872 LNAI |

ISSN (Print) | 0302-9743 |

ISSN (Electronic) | 1611-3349 |

### Other

Other | 4th International Workshop on Analogical and Inductive Inference, AII 1994 and 5th International Workshop on Algorithmic Learning Theory, ALT 1994 |
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Country | Germany |

City | Reinhardsbrunn Castle |

Period | 94/10/10 → 94/10/15 |

### ASJC Scopus subject areas

- Theoretical Computer Science
- Computer Science(all)

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## Cite this

*Algorithmic Learning Theory - 4th International Workshop on Analogical and Inductive Inference, AII 1994 and 5th International Workshop on Algorithmic Learning Theory, ALT 1994, Proceedings*(pp. 560-573). (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics); Vol. 872 LNAI). Springer Verlag.