I argue that the ability to compute phrase structure grammars is indicative of a particular kind of thought. This type of thought that is only available to cognitive systems that have access to the computations that allow the generation and interpretation of the structural descriptions of phrase structure grammars. The study of phrase structure grammars, and formal language theory in general, is thus indispensable to studies of human cognition, for it makes explicit both the (...) unique type of human thought and the underlying mechanisms in virtue of which this thought is made possible. (shrink)

We sketch an axiomatic reformalization of Generalized Phrase StructureGrammar (GPSG) – a definition purely within the language ofmathematical logic of the theory GPSG embodies. While this treatment raisesa number of theoretical issues for GPSG, our focus is not thereformalization itself but rather the method we employ. The model-theoreticapproach it exemplifies can be seen as a natural step in the evolution ofconstraint-based theories from their grammar-based antecedents. One goal ofthis paper is to introduce this approach to a broader audience and (...) todemonstrate its application to an existing theory. As such, it joins agrowing literature of similar studies. Prior studies, however, have had anumber of weaknesses – they generally offer little in the way ofconcrete examples of the advantages the approach has to offer, theytypically ignore significant portions of the theories they address, and, byfully abstracting away from the notion of grammar mechanism, they largelyabandon the possibility of establishing meaningful complexity results. Thesecond goal of the paper is to address these issues. Our thrust is to sketchthe reformalization sufficiently to illustrate the way in which it capturesFeature Specification Defaults (FSDs) and the Exhaustive Constant PartialOrdering (ECPO) property. Our definition of FSDs is considerably simplifiedrelative to the original formalization and is free of the procedural flavorthat has led some to assume that FSDs are inherently dynamic. Our treatmentof ECPO uncovers a gap in its definition in the context of partialcategories that has heretofore gone unnoticed. We offer these as ademonstration of the kind of insight that a model-theoretic reinterpretationcan bring to an existing theory. Further, since these are the types ofproperties that prior studies in this genre have failed to address, FSDs andECPO provide a means for us to explore the limitations of these approachesand to offer ways of overcoming them. Finally, the logical framework weemploy has a well defined generative capacity – definability in thisframework characterizes strong context-freeness in a particular sense. Thus,despite being more abstract than its constraint-based predecessors, themodel-theoretic approach, as exemplified here, can offer stronger complexityresults than are typically available in the constraint-based framework. (shrink)

Unsupervised grammar induction systems commonly judge potential constituents on the basis of their effects on the likelihood of the data. Linguistic justifications of constituency, on the other hand, rely on notions such as substitutability and varying external contexts. We describe two systems for distributional grammar induction which operate on such principles, using part-of-speech tags as the contextual features. The advantages and disadvantages of these systems are examined, including precision/recall trade-offs, error analysis, and extensibility.

This paper describes a system for extracting typed dependency parses of English sentences from phrase structure parses. In order to capture inherent relations occurring in corpus texts that can be critical in real-world applications, many NP relations are included in the set of grammatical relations used. We provide a comparison of our system with Minipar and the Link parser. The typed dependency extraction facility described here is integrated in the Stanford Parser, available for download.

In [2], Bar-Hillel, Gaifman, and Shamir prove that the simple phrase structure grammars (SPGs) defined by Chomsky are equivalent in a certain sense to Bar-Hillel's bidirectional categorial grammars (BCGs). On the other hand, Cohen [3] proves the equivalence of the latter ones to what the calls free categorial grammars (FCGs). They are closely related to Lambek's syntactic calculus which, in turn, is based on the idea due to Ajdukiewicz [1]. For the reasons which will be discussed in the (...) last section, Cohen's proof seems to be at least incomplete. This paper yields a direct proof of the equivalence ofFCGs andSPGs. (shrink)

In [2], Bar-Hillel, Gaifman, and Shamir prove that the simple phrase structure grammars dened by Chomsky are equivalent in a cer- tain sense to Bar-Hillel's bidirectional categorial grammars . On the other hand, Cohen [3] proves the equivalence of the latter ones to what he calls free categorial grammars . They are closely related to Lambek's syntactic calculus which is, in turn, based on the idea due to Ajdukiewicz [1]. For some reasons, Cohen's proof seems to be at (...) least in- complete. Here, I give a short outline of the direct proof of the equivalence between SF G's and F CG's. (shrink)

In this paper, we shall present a generalization of phrase structure grammar, in which all functional categories have type restrictions, that is, their argument types are specific domains. In ordinary phrase structure grammar, there is just one universal domain of individuals. The grammar does not make a distinction between verbs and adjectives in terms of domains of applicability. Consequently, it fails to distinguish between sentences like every line intersects every line, which is well typed, and every (...) line intersects every point, which is ill typed.Our generalization relates to ordinary phrase structure grammar in the same way as the higherlevel constructive type theory of Martin-Löf relates to the simple type theory of Church . Simple type theory has been used in linguistics and related with phrase structure grammar, especially in the tradition based on the work of Montague .Our definition of the grammar will be more formal than Montague's in the sense that we shall use a formal metalanguage, that of constructive type theory, for defining both the object language and its interpretation. The grammar, both syntax and semantics, is thus readily implementable in the type-theoretical proof system ALF . Inside type theory, a distinction can be made between the object language and the model, in other words, between syntactic and semantic types. It will turn out that the object language cannot be defined independently of the model, as in ordinary Tarski semantics. This is a direct consequence of introducing the typing restrictions.The grammar presented here can be seen as a formal linguistic elaboration of the work presented in Ranta 1991 and 1994. The organization of generative grammar as categorial grammar followed by sugaring should now look more familiar to the linguist, as the grammatical formalism on which sugaring operates is no longer full type theory but a set of phrase structure trees. (shrink)

Some modifications are suggested to recent (1985) generalised phrase-structure grammar which make the formalism more suitable to computational use, and at the same time provide a clear and elegant redefinition for parts of the formalism which are standardly complex and ill-defined. It is shown how the feature-instantiation principles can be represented as explicit rules in a format similar to metarules, and how a grammar of four parts, immediate-dominance rules, linear-precedence rules, metarules, and these new propagation rules, can be (...) used to produce the ordinary GPSG analyses of English. Methods of computational implementation are discussed, in particular it is suggested that the parts of the grammar are most conveniently interpreted as instructions as to how to produce a set of context-free phrase-structure rules which can be used with a simple left-corner parser. (shrink)

The restrictive grammatical format suggested in GPSG provides an extremely interesting alternative to transformational approaches to grammar. However, we have seen that the way the grammar is currently organized, it will in certain cases fail to give the correct interpretation to sentences with displaced constituents. Whenever a left or rightward displaced constituent contains an element that can stand in an anaphoric relation with some other element in the sentence, i.e. contains a quantifier or a pronoun, the semantic rules as given (...) do not provide the intended reading. It should be made clear, however, that this shortcoming pertains to one particular type of GPSG, namely one whose interpretation procedures make use of lambda abstraction. The problematic cases addressed here do not by themselves invalidate the syntactic framework of a GPSG. It seems quite plausible that one could construct a semantics that does not depend on lambda conversion, in which case the problem addressed in this note is presumably no longer relevant. One such proposal is put forward in Cooper (forthcoming) where a non-movement syntax is combined with interpretation procedures that do not involve translation into a lambda calculus. (shrink)

The SRL of King is a sound, complete and decidable logic designed specifically to support formalisms for the HPSG of Pollard and Sag. The SRL notion of modellability in a signature is particularly important for HPSG, and the present paper modifies an elegant method due to Blackburn and Spaan in order to prove that – modellability in each computable signature is 1 0 – modellability in some finite signature is 1 0 -hard, and – modellability in some finite signature is (...) decidable. (shrink)

This paper investigates the semantics of measure phrases in Japanese. Based on new data, we argue that the interpretation of measure phrases in Japanese is sensitive to scale structure such that (i) measure phrases are introduced by a degree morpheme that selects only for gradable predicates whose scale contains a minimal element (i.e., a lower closed scale) and (ii) violations to this restriction are repaired via coercion, which forces a comparative interpretation with a contextually determined standard and hence a (...) minimal element. We compare the Japanese facts to data in other languages and argue that the requirement of having a minimal element is not specific to Japanese, but universal. We show that languages may vary in how they deal with potential violations of this universal constraint, including coercion of a contextually recoverable derived minimal element (Japanese), ungrammaticality (e.g., Spanish, Korean, Russian), and a hybrid system of ungrammaticality for some adjectives and allowed constraint violation for others (e.g., English, German, Italian). (shrink)

I should like to express my gratitude to my supervisor, Professor H. Schultink, whose criticisms and careful reading helped me to improve considerably upon the clarity of exposition while I wrote this study, and whose seemingly innocent requests to elaborate confronted me time and again with the need of revising or abandoning ideas I thought stood on firm ground. His support, and Dr. M. C. van den Toom's gratefully acknowl edged willingness to read and evaluate the manuscript enabled me to (...) present this work as a thesis in the University of Utrecht. In more than one way, lowe a debt to Albert Kraak, Professor of Linguistics in the University of Nijmegen. His inspiring enthusiasm awakened my interest in linguistics when I was a student of his. He in troduced me to transformational grammar at a time when it seemed almost improper to talk about it, and the stimulating experience of writing a book on Dutch syntax together with him taught me invaluable lessons. I should also like to thank my friend and colleague Henk Verkuyl, to gether with whom I prepared an article on the subject of measuring duration in Dutch. Without our stimulating discussions on the subject, the fourth chapter of this study could never have been written in the present form. I am also indebted to him for criticisms and helpful suggestions. At an early stage I profited greatly from discussions with Pieter A. M. (shrink)