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this paper, we study the problem of lexicalizing context-free grammars and show that it enables faster processing. In previous attempts to take advantage of lexicalization, a variety of lexicalization procedures have been developed that convert context-free grammars (CFGs) into equivalent lexicalized grammars. However, these procedures typically suffer from one or more of the following problems

We describe a categorial system (PPTS) based on partial proof trees (PPTs) as the building blocks of the system. The PPTs are obtained by unfolding the arguments of the type that would be associated with a lexical item in a simple categorial grammar. The PPTs are the basic types in the system and a derivation proceeds by combining PPTs together. We describe the construction of the finite set of basic PPTs and the operations for combining them. PPTS can be viewed as a categorial system incorporating some of the key insights of lexicalized tree adjoining grammar, namely the notion of an extended domain of locality and the consequent factoring of recursion from the domain of dependencies. PPTS therefore inherits the linguistic and computational properties of that system, and so can be viewed as a `middle ground' between a categorial grammar and a phrase structure grammar. We also discuss the relationship between PPTS, natural deduction, and linear logic proof-nets, and argue that natural ...

In this paper the Chomsky Conjecture is proved: all languages recognized by the Lambek calculus are context free.

Recent results have established that there is a family of languages flint is exactly the clazs of languages generated by three independently developed grammar formalisms: Tree Adjoining Grammars, Head Grammars, and Linear Indexed Grammars. In this paper we show flint Combinawry Categorial Grammars also generates the same class of languages. We discuss the structmal descriptions produc l by Combinatory Categorial Orammars and compare them to those of grammar formalisms in th ias of Linear Context-Fre Rewriting Systems. We also discuss crtain extensions of Combinatory gorial Ommmars and their effect on the weak geneative capacity.

this paper, we will study the possibilities for applying lexical rules to the analysis of English syntax, and in particular the structure of the verb phrase. We will develop a lexicon whose empirical coverage extends to the full range of verb subcategories, complex adverbial phrases, auxiliaries, the passive construction, yes/no questions and the particularly troublesome case of predicatives. The effect of a lexical rule, in our system, will be to produce new lexical entries from old lexical entries. The similarity between our system and the metarule system of generalized phrase-structure grammar (GPSG, as presented in Gazdar, et al. 1985) is not coincidental. Our lexical rules serve much the same purpose as metarules in GPSG, which were restricted to lexical phrase structure rules. The similarity is in a large part due to the fact that with the universal phrase-structure schemes being fixed, the role of a lexical category assignment in effect determines phrase-structure in much the same way as a lexical category entry and lexical phrase-structure rule determines lexical phrase-structure in GPSG. Our lexical rules will also bear a relationship to the lexical rules found in lexical-functional grammar (LFG, see Bresnan 1982), as LFG rules are driven by the grammatical role assigned to arguments. Many of our analyses were first applied to either LFG or GPSG, as these were the first serious linguistic theories based on a notion of unification. In the process of explaining the basic principles behind categorial grammar and developing our lexical rule system, we will establish a categorial grammar lexicon with coverage of English syntactic constructions comparable to that achieved within published accounts of the GPSG or LFG frameworks. Language, at its most abstract level, i...

In this paper we prove the Chomsky Conjecture (all languages recognized by the Lambek calculus are context-free) for both the full Lambek calculus and its product-free fragment. For the latter case we present a construction of context-free grammars involving only product-free types.

The Lambek calculus, an intuitionistic fragment of Linear Logic, has recently been rediscovered by linguists. Due to its built-in hypothetical reasoning mechanism, it allows for describing a certain range of those phenomena in natural language syntax which involve incomplete subphrases or moved constituents. Previously, it seemed unclear how to extent traditional parsing techniques in order to incorporate reasoning about incomplete phrases, without causing the undesired effect of derivational equivalences. It turned out that the Lambek calculus offers a framework to formulate equivalent but more implementation-oriented calculi where this problem does not occur. In this paper, such a theorem prover for the Lambek calculus, i.e. a parser for Lambek categorial grammars, is defined. Permutations of proof steps which would cause derivational equivalence in a purely sequential formulation do not play a role in a (pseudo-)parallel approach which is based on a lemma table or a "chart". At the...

Grammars that expect words from the lexicon may be at odds with the transparent projection of syntactic and semantic scope relations of smaller units. We propose a morphosyntactic framework

This thesis proposes a strongly lexicalist approach to machine translation and applies it to the translation of spatial prepositions and prepositional expressions between English and Spanish. Bilingual contrastive knowledge resides solely in the bilingual lexicon and is structured in the form of correspondences between sets of source and target language lexemes related through indices. The resulting architecture maximizes the independence of the monolingual and bilingual components. This independence is demonstrated by developing a grammar of Spanish which is significantly different in its constructions from its analogous English grammar. In particular, relative clauses are analysed through a single rule that allows gaps in subject position, while clitic climbing and doubling are handled through mechanisms not normally found in grammatical descriptions of English. Bilingual lexical rules, in conjunction with the bilingual lexicon, constitute a single, motivated and well defined mechani...