tailieunhanh - Báo cáo khoa học: "Parsing Idioms in Lexicalized TAGs"

We show how idioms can be parsed in lexiealized TAGs. We rely on extensive studies of frozen phrases pursued at ) that show that idioms are pervasive in natural language and obey, generally speaking, the same morphological and syntactical patterns as 'free' structures. By idiom we mean a structure in which some items are lexically frozen and have a semantics that is not compositional. We thus consider idioms of different syntactic categories : NP, S, adverbials, compound prepositions, in both English and French. In lexicalized TAGs, the same grammar is used for idioms as for 'free' sentences. We assign. | Parsing Idioms in Lexicalized TAGS Anne Abeillé and Yves Schabes Laboratoire Automatique Documentaire et Linguistique University Paris 7 2 place Jussieu 75005 Paris France and Department of Computer and Information Science University of Pennsylvania Philadelphia PA 19104-6389 USA abeille schabes@ ABSTRACT We show how idioms can be parsed in lexical-ized TAGs. We rely on extensive studies of frozen phrases pursued at that show that idioms are pervasive in natural language and obey generally speaking the same morphological and syntactical patterns as free structures. By idiom we mean a structure in which some items are lexically frozen and have a semantics that is not compositional. We thus consider idioms of different syntactic categories NP s adverbials compound prepositions. in both English and French. In lexicalized TAGs the same grammar is used for idioms as for free sentences. We assign them regular syntactic structures while representing them semantically as one non-compositional entry. Syntactic transformations and insertion of modifiers may thus apply to them as to any free structures. Unlike previous approaches their variability becomes the general case and their being totally frozen the exception. Idioms are generally represented by extended elementary trees with heads made out of several items that need not be contiguous with one of the items serving as an index. When an idiomatic tree is selected by this index lexical items are attached to some nodes in the tree. Idiomatic trees are selected by a single head node however the head value imposes lexical values on other nodes in the tree. This operation of attaching the head item of an idiom and its lexical parts is called lexical attachment. The resulting tree has the lexical items corresponding to the pieces of the idiom already attached to it. This work is partially supported for the second author by ARO grant DAA29-84-9-007 DARPA grant N0014-85-K0018 NSF grants MCS-82-191169