Abstract
We present a context-free approximation of unification-based grammars, such as HPSG or PATR-II. The theoretical underpinning is established through a least fixpoint construction over a certain monotonic function. In order to reach a finite fixpoint, the concrete implementation can be parameterized in several ways , either by specifying a finite iteration depth, by using different restrictors, or by making the symbols of the CFG more complex adding annotations a la GPSG. We also present several methods that speed up the approximation process and help to limit the size of the resulting CF grammar.- Anthology ID:
- 2000.iwpt-1.15
- Volume:
- Proceedings of the Sixth International Workshop on Parsing Technologies
- Month:
- February 23-25
- Year:
- 2000
- Address:
- Trento, Italy
- Venue:
- IWPT
- SIG:
- SIGPARSE
- Publisher:
- Association for Computational Linguistics
- Note:
- Pages:
- 135–146
- Language:
- URL:
- https://aclanthology.org/2000.iwpt-1.15
- DOI:
- Cite (ACL):
- Bernd Kiefer and Hans-Ulrich Krieger. 2000. A Context-free Approximation of Head-driven Phrase Structure Grammar. In Proceedings of the Sixth International Workshop on Parsing Technologies, pages 135–146, Trento, Italy. Association for Computational Linguistics.
- Cite (Informal):
- A Context-free Approximation of Head-driven Phrase Structure Grammar (Kiefer & Krieger, IWPT 2000)
- PDF:
- https://preview.aclanthology.org/paclic-22-ingestion/2000.iwpt-1.15.pdf