作者: Aravind K Joshi , K. Vijay-Shanker
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摘要: Many current grammar formalisms used in computational linguistics take a unification-based approach that use structures (called feature structures) containing sets of feature-value pairs. In this paper, we describe to Tree Adjoining Grammars (TAG). The resulting formalism (UTAG) retains the principle factoring dependencies and recursion is fundamental TAGs. We also extend definition UTAG include lexicalized TAGs (see [Schabes et al., 1988]). give some linguistic examples using informally discuss descriptive capacity UTAG, comparing it with other unificationbased formalisms. Finally, based on theory underlying TAGs, propose stipulations can be placed grammars. particular, stipulate associated nodes an elementary tree are bounded ( there analogous stipulation GPSG). satisfy these equivalent TAG. Thus, even stipulations, UTAGs have more power than CFG-based unification grammars same stipulations. Comments University Pennsylvania Department Computer Information Science Technical Report No. MSCIS-91-25. This technical report available at ScholarlyCommons: http://repository.upenn.edu/cis_reports/762 Unification-Based MS-CIS-91-25 LINC LAB 199 K. Vijay-S hanker (University Delaware) Aravind Joshi Pennsylvania) School Engineering Applied Philadelphia, PA 19104-6389 March 1991 [[To appear "Unification-Based Grammars" (ed. Jurgen Wedekind), MIT PRESS 199111 UnificationBased Grammars't Vijay-Shanker Dept. & Sciences Delaware Newark, DE 19711 19104 US.A U.S.A.