Link2Tree: A Dependency-Constituency Converter

Link2Tree is a dependency-constituency converter written in PROLOG and developed for Link Grammar and ExtrAns. This thesis describes its architecture and functionality in detail. It demonstrates what constraints on link structures make them equivalent to constitent structures. This equivalence makes Link2Tree a deterministic converter, since a linkage corresponds to exactly one constituent tree. However, the linkages may need some preprocessing, which is called ‘relinking’ in Link2Tree, to ensure their equivalence to a particular form of constituent structure. The development and implementation of a conversion algorithm is described. Link2Tree is a flexible program, which enables users to specify the form of X-bar theory they desire for the constituent structure delivered by the converter. Furthermore, users can freely choose the features they want to use in the constituent output. The possibilities of Link2Tree make it applicable to Government & Binding as well as PSG structures. If its rule set is tuned accordingly, Link2Tree is able to preserve all information that is stored in linkages for the constituent structures it returns. The thesis is divided into three parts: Part I states the basic theoretical concepts of dependency, and link grammar in particular, as well as constituency. Part II describes the conversion algorithm as well as the architecture and functionality of the converter. Part III explains how users can develop their own rule set for the converter. A note to the reader This thesis comprises the theoretical background as well as a documentation of the Prolog program Link2Tree. If it is read from beginning to end, I strongly encourage the reader to have the program code at hand, especially when reading parts II and III. If this paper is used as a manual to Link2Tree, I recommend using the predicate index at the end of the thesis as a starting point for specific problems. If a particular predicate is not found in the predicate index, one may search for the predicate which calls it. The implementer wanting to integrate Link2Tree into a larger system is referred to section 4 for the most basic program specifications, and to section 5 for a general overview of the program. A description of the installation and startup of Link2Tree is provided in appendix A.

[1]  Rolf Schwitter,et al.  ANSWER EXTRACTION USING A DEPENDENCY GRAMMAR IN EXTRANS , 2000 .

[2]  Igor Mel’čuk,et al.  Dependency Syntax: Theory and Practice , 1987 .

[3]  Haim Gaifman,et al.  Dependency Systems and Phrase-Structure Systems , 1965, Inf. Control..

[4]  Richard Hudson,et al.  English word grammar , 1995 .

[5]  Michael A. Covington.  GB theory as dependency grammar , 1992 .

[6]  Geoffrey K. Pullum,et al.  Generalized Phrase Structure Grammar , 1985 .

[7]  Noam Chomsky,et al.  The Minimalist Program , 1992 .

[8]  Mark Newson,et al.  乔姆斯基的普遍语法教程 = Chomsky's universal grammar : an introduction : , 1988 .

[9]  Noam Chomsky,et al.  Lectures on Government and Binding , 1981 .

[10]  Ivan A. Sag,et al.  Syntactic Theory: A Formal Introduction , 1999, Computational Linguistics.

[11]  H. Somers,et al.  On the validity of the complement-adjunct distinction in valency grammar , 1984 .

[12]  D. G. Hays.  Dependency Theory: A Formalism and Some Observations , 1964 .

[13]  Paul Bennett.  A course in generalized phrase structure grammar , 1995 .

[14]  Daniel Dominic Sleator,et al.  Parsing English with a Link Grammar , 1995, IWPT.

[15]  Kalevi Tarvainen.  Einführung in die Dependenzgrammatik , 1983 .

[16]  Rolf Schwitter,et al.  ExtrAns, an answer extraction system , 2000 .

[17]  Gerold Schneider,et al.  A Linguistic Comparison of Constituency, Dependency and Link Grammar , 1998 .

[18]  J. E. Miller,et al.  Concise Encyclopedia of Syntactic Theories , 1996 .

[19]  Michael A. Covington.  An Empirically Motivated Reinterpretation of Dependency Grammar , 1994, ArXiv.

[20]  C. Habel,et al.  Language , 1931, NeuroImage.

[21]  M.McGee Wood,et al.  Natural language processing in Prolog , 1990 .

[22]  Lucien Tesnière.  Éléments de syntaxe structurale , 1959 .

[23]  Andrew Radford,et al.  Syntactic Theory and the Structure of English: A Minimalist Approach , 1997 .

[24]  Ivan A. Sag,et al.  Book Reviews: Head-driven Phrase Structure Grammar and German in Head-driven Phrase-structure Grammar , 1996, CL.