Tree-adjoining grammar

About: Tree-adjoining grammar is a research topic. Over the lifetime, 2491 publications have been published within this topic receiving 57813 citations.

Sub-protocol-evaluators for attribute grammars

Abstract: This paper presents a new strategy for evaluating attribute grammars, sub-protocol attribute evaluation, and gives an algorithm for constructing sub-protocol-evaluators. Sub-protocol-evaluators can be built for any non-circular attribute grammar; this paper describes how to construct them for absolutely noncircular grammars [4]. Sub-protocol-evaluators are most easily understood as a simple optimization of another evaluator we call the protocol-evaluator. The protocol-evaluator has elements in common with the tree-walk evaluator of Kennedy-Warren [4] and with Nielson's direct evaluator [6]; it can be viewed as a refinement of each of these. Furthermore, the uniform AGs, proposed by Warren [9], and the ordered AGs, proposed by Kastens [3], are both subclasses of grammars for which especially efficient protocol-evaluators can be built.

Learning categorial grammars

Abstract: In 1967 E. M. Gold published a paper in which the language classes from the Chomsky-hierarchy were analyzed in terms of learnability, in the technical sense of identification in the limit. His results were mostly negative, and perhaps because of this his work had little impact on linguistics. In the early eighties there was renewed interest in the paradigm, mainly because of work by Angluin and Wright. Around the same time, Arikawa and his co-workers refined the paradigm by applying it to so-called Elementary Formal Systems. By making use of this approach Takeshi Shinohara was able to come up with an impressive result; any class of context-sensitive grammars with a bound on its number of rules is learnable. Some linguistically motivated work on learnability also appeared from this point on, most notably Wexler & Culicover 1980 and Kanazawa 1994. The latter investigates the learnability of various classes of categorial grammar, inspired by work by Buszkowski and Penn, and raises some interesting questions. We follow up on this work by exploring complexity issues relevant to learning these classes, answering an open question from Kanazawa 1994, and applying the same kind of approach to obtain (non)learnable classes of Combinatory Categorial Grammars, Tree Adjoining Grammars, Minimalist grammars, Generalized Quantifiers, and some variants of Lambek Grammars. We also discuss work on learning tree languages and its application to learning Dependency Grammars. Our main conclusions are: - formal learning theory is relevant to linguistics, - identification in the limit is feasible for non-trivial classes, - the `Shinohara approach' -i.e., placing a numerical bound on the complexity of a grammar- can lead to a learnable class, but this completely depends on the specific nature of the formalism and the notion of complexity. We give examples of natural classes of commonly used linguistic formalisms that resist this kind of approach, - learning is hard work. Our results indicate that learning even `simple' classes of languages requires a lot of computational effort, - dealing with structure (derivation-, dependency-) languages instead of string languages offers a useful and promising approach to learnabilty in a linguistic context

Algebraic Specification Grammars: A Junction between Module Specifications and Graph Grammars

Abstract: Algebraic specification grammars have recently been introduced implicitly by the second author as a new kind of graph grammars in order to generate algebraic specifications using productions and derivations. In fact, in the well-known algebraic approach to graph grammars, also known as "Berlin-approach", we mainly have to replace the category of graphs by the category of algebraic specifications to obtain the basic definitions, constructions and results for this new kind of grammars. Since a production in an algebraic specification grammars corresponds exactly to an interface of an algebraic module specification for modular software systems this new kind of grammars can be used for modular system design. For this purpose we give an overview how notions in the theory of grammars and that of module specifications correspond to each other and discuss how both theories can benefit from each other. Concerning full technical detail and proofs we refer to other published or forthcoming papers.