Unification grammars are known to be Turing-equivalent; given a grammar G and a word w, it is undecidable whether w L(G). In order to ensure decidability, several constraints on grammars, commonly known as off-line parsability (OLP), were suggested, such that the recognition problem is decidable for grammars which satisfy OLP. An open question is whether it is decidable if a given grammar satisfies OLP. In this paper we investigate various definitions of OLP and discuss their interrelations, proving that some of the OLP variants are indeed undecidable. We then present a novel, decidable OLP constraint which is more liberal than the existing decidable ones.
|Number of pages||36|
|Journal||Journal of Logic, Language and Information|
|State||Published - Mar 2005|
Bibliographical noteFunding Information:
The work of Nissim Francez was partially funded by the Vice-President’s fund for the promotion of research at the Technion. The work of Shuly Wintner was supported by the Israeli Science Foundation (grant no. 136/01).
- Off-line parsability
- Parsing termination
- Unification grammars
ASJC Scopus subject areas
- Computer Science (miscellaneous)
- Linguistics and Language