Division of Informatics

Forrest Hill & 80 South Bridge

## Research Paper #496 | |
---|---|

Title: | Languages Generated by Two-Level Morphological Rules |

Authors: | Ritchie,GD |

Date: | Apr 1991 |

Presented: | To appear in "Computational Linguistics" |

Keywords: | |

Abstract: | The two-level model of morphology and phonolgy arose from work on finite-state machine descriptions of phonological phenomena. However, the two-level rule notation can be given a precise declarative semantics in terms of the segmentation of sequences of pairs of symbols, quite independently of any computational representation as sets of finite-state transducers. Thus defined, the two-level model can be shown to be less powerful, in terms of weak generative capacity, than parallel intersections of arbitrary finite-state transducers without empty transitions (the usual computational representation). However, if a special boundary symbol is permitted, the full family of regular languages can be generated. Two-level morphological grammars may, without loss of generality, be written in a simplified normal form. The set of two-level generated languages can be shown to be closed under intersection, but not under union or complementation. |

Download: | NO ONLINE COPY |