tailieunhanh - Báo cáo khoa học: "EFFICIENT PARSING FOR FRENCH*"

Parsing with categorial grammars often leads to problems such as proliferating lexical ambiguity, spurious parses and overgeneration. This paper presents a parser for French developed on an unification based categorial grammar (FG) which avoids these problem s. This parser is a bottom-up c hart parser augmented with a heuristic eliminating spurious parses. The unicity and completeness of parsing are proved. | EFFICIENT PARSING FOR FRENCH Claire Gardent University Blaise Pascal - Clermont II and University of Edinburgh Centre for Cognitive Science 2 Buccleuch Place Edinburgh EH89LW SCOTLAND UK Gabriel G. Bès Pierre-Franẹois Jurie and Karine Baschung Université Blaise Pascal - Clermont II Formation Doctorale Linguistique et Informatique 34 Ave. Carnot 63037 Clermont-Ferrand Cedex FRANCE ABSTRACT Parsing with categorial grammars often leads to problems such as proliferating lexical ambiguity spurious parses and overgeneration. This paper presents a parser for French developed on an unification based categorial grammar FG which avoids these problems. This parser is a bottom-up chart parser augmented with a heuristic eliminating spurious parses. The unicity and completeness of parsing are proved. INTRODUCTION Our aim is twofold. First to provide a linguistically well motivated categorial grammar for French henceforth FG which accounts for word order variations without overgenerating and without unnecessary lexical ambiguities. Second to enhance parsing efficiency by eliminating spurious parses . parses with different derivation trees but equivalent semantics. The two goals are related in that the parsing strategy relies on properties of the grammar which are indepen-dently motivated by the linguistic data. Nevertheless the knowledge embodied in the grammar is kept independent from the processing phase. 1. LINGUISTIC THEORIES AND WORD ORDER Word order remains a pervasive issue for most linguistic analyses. Among the theories most closely related to FG Unification Categorial Grammar UCG Zeevat et al. 1987 Combinatory Categorial Grammar CCG Steedman 1985 Steedman 1988 Categorial Unification Grammar CUG Karttunen 1986 and Head-driven Phrase Structure Grammar HPSG Pollard Sag 1988 all present inconveniences in theữ way of dealing with word order as regards parsing efficiency and or linguistic data. The work reported here was carried out in the ES PRIT Project 393 ACORD The .