RenTAL (Grammar converter for LTAG)
RenTAL (Renderer Engine for Tree Adjoining Languages) is a system which generates HPSG-style grammars by converting existing (FB-)LTAG grammars. The system is developed and maintained mainly by Yoshinaga, a member of Tsujii Lab.
The conversion preserves strong equivalence where the obtained HPSG grammar generates the same derivation trees as the FB-LTAG grammar.
This system thus allows HPSG-based applications to make use of existing LTAG grammars without losing LTAG syntactic analysis.
It also enables a precise comparison between the two formalisms both computationally and linguistically.
The system converts LTAG elementary trees into HPSG feature structures by encoding a tree structure in a stack. A set of pre-determined rule manipulates the stack to emulate substitution and adjunction.
- Conversion of elementary trees:
LTAG elementary trees are converted into HPSG lexical entries after they are converted into canonical elementary trees which satisfy the following conditions.
- Condition 1: A tree must have only one anchor.
- Condition 2: All subtrees must contain at least one anchor.
Conversion of a canonical elementary tree is straightforward, that is,by regarding the leaf nodes as its arguments, and store them in a stack. Elementary trees which violates Condition 1 are converted into canonical ones by dividing them into single-anchored parts. Elementary trees which violates Condition 2 are converted into canonical ones by substituting the deepest nodes in the subtrees with initial trees.
- Grammar rules:
A Grammar rule for Substitution is straightforward, that is, it consumes one element of the arguments and percolates the rest to the mother. One for adjunction concatenates both arguments of the daughters and percolates it to the mother.
You can find it in tujiilab software package page.
NOTE:RenTAL system is implemented in the programming language LiLFeS. See also the LiLFeS home page.
[1] YOSHINAGA Naoki, MIYAO Yusuke, TORISAWA Kentaro, and TSUJII Jun'ichi. 2001. Resource sharing among HPSG and LTAG communities by a method of grammar conversion from FB-LTAG to HPSG. In the Proceedings of ACL/EACL 2001 Workshop on Sharing Tools and Resouces for Research and Education. pp. 39--46.
[2] YOSHINAGA Naoki, MIYAO Yusuke. 2001. Grammar Conversion from LTAG to HPSG. To appear in the European Student Journal on Language and Speech, a special issue on the language sections of the 6th ESSLLI strudent session. 2002. (the original paper presented in the student session).
[3] YOSHINAGA Naoki, MIYAO Yusuke, TORISAWA Kentaro, and TSUJII Jun'ichi. 2001. Efficient LTAG Parsing using HPSG parsers. In the Proceedings of the PACLING 2001, pp. 342--351.
[4] YOSHINAGA Naoki, MIYAO Yusuke, and TSUJII Jun'ichi. 2002. A formal proof of strong equivalence for a grammar conversion from LTAG to HPSG-style. To appear in the proceedings of the TAG+6 Workshop.
All questions and suggestions are welcome. Please send e-mail to YOSHINAGA Naoki (yoshinag@is.s.u-tokyo.ac.jp)
$ Last modified at Wed May 08 06:30:07 2002 $