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Abstract not found

Under categorial grammars that have powerful rules like composition, a simple n-word sentence can have exponentially many parses. Generating all parses is inefficient and obscures whatever true semantic ambiguities are in the input. This paper addresses the problem for a fairly general form of Combinatory Categorial Grammar, by means of an efficient, correct, and easy to implement normal-form parsing technique. The parser

ht capture the obvious intuitions concerning constituency in a sentence like John must leave by identifying the VP leave and the NP John as the arguments of the tensed verb must, and the verb itself as a function combin- ing to its right with a VP, to yield a predicate -- that is, a leftward-combining function-from-NPs-into-sentences. One common "slash" notation for the types of such functions expresses them as lriples of the form <result, direction, argu. me. hi>, where result and argument are themselves syntactic types, and direction is indicated by "f' (for rightwardcombining functions) or ' (for leftward). Must then gets the following type-assignment: (1) must :- (SNP}/VP In pure categorial grammar, the only other element is a single "combinatory" rule of Functional Application, which gives rise to the following two instances: 1 1 All combinatory mlus are written as productions in the present paper, in contrast with the reduction rule notation used in the earlier papers. The cha

A type of ‘non-traditional constituents’ motivates an extended class of Combinatory Categorial Grammars, CCGs with Generalized Type-Raised Categories (CCG-GTRC) involving variables. Although the class of standard CCGs is known to be polynomially parsable, use of variables suggests more complexity for processing GTRCs. This paper argues that polynomial parsing is still possible for CCG-GTRC from practical and theoretical points of view. First, we show that an experimental parser runs polynomially in practice on a realistic fragment of Japanese by eliminating spurious ambiguity and excluding genuine ambiguities. Then, we present a worst-case polynomial recognition algorithm for CCG-GTRC by extending the polynomial algorithm for the standard CCGs.

. We present a natural language interface for Japanese that relies on semantically driven parsing in that it applies syntactic analysis only if necessary for disambiguation. For this purpose we utilize a categorial parser which also analyzes incomplete or ungrammatical input efficiently. The complete linguistic analysis is performed by means of deductive object-oriented database (DOOD) technology so that we achieve an integrated framework with the target application. The interface has been applied successfully to the question support facilities of the VIENA Classroom hypermedia teaching system. 1 Introduction In spite of the large amount of work on natural language interfaces, they are today still far away from widespread practical use (for a good recent survey see [1]). The reason for this are the many still existing limitations which are caused by two main factors: missing customization, resulting in unexpected restrictions, and missing integration, responsible for insufficient perf...

Steedman (198,5, 1987) and others have proposed that Categorial Grammar, a theory of syntax in which grammatical categories are viewed as functions, be augmented with operators such as functional composition and type raising in order to analyze noncanonical" syntactic constructions such as wh- extraction and node raising. A consequence of these augmentations is an explosion of semantically equivalent derivations admitted by the grammar. The present, work proposes a method for circumventing this spurious ambiguity problem. It involves deriving new, specialized combinators and replacing the orginai basic combinators with these derived ones. In this paper, examples of these p'edictive combinator are offered and their effects illustrated. An l- gorithm for deriving them, s well s a discussion of their semantics, will be presented in forthcoming work.

In this paper we present a natural language interface architecture, which is used for accessing FAQ knowledge bases. Since one of the main obstacles to the efficient use of natural language interfaces is the high amount of required manual knowledge engineering, we provide an adaptive architecture to automate the acquisition of linguistic knowledge. We apply a machine learning module based on an XSE (eXtended Semantic Enumeration) tree to activate linguistic tests from semantic, syntactic, and pragmatic analysis during the traversal of the tree. The XSE-tree is built automatically based on past questions without the need for any additional linguistic knowledge.

This paper is focused on the extension of Categorial Unification Grammar (CUG) in order to achieve a compact grammatical representation scheme for the syntactic analysis of free word order languages. The resulting grammar was applied to the implementation of an efficient parser within a German natural language interface to a deductive database by making use of the Integrated Deductive Approach in which the interface constitutes a fully integrated part of the database system. 1.