Context-sensitive grammar

About: Context-sensitive grammar is a research topic. Over the lifetime, 1938 publications have been published within this topic receiving 45911 citations. The topic is also known as: CSG.

The complexity of parsing with extended categorial grammars

Abstract: Instead of incorporating a gap-percolation mechanism for handling certain "movement" phenomena, the extended categorial grammars contain special inference rules for treating these problems. The Lambek categorial grammar is one representative of the grammar family under consideration. It allows for a restricted use of hypothetical reasoning. We define a modification of the Cocke-Younger-Kasami (CKY) parsing algorithm which covers this additional deductive power and analyze its time complexity.

Subclasses of Attribute Grammars

Abstract: This thesis is a contribution to the development of a formal theory for attribute grammars, their languages and their translations. There are given precise definitions of an attribute grammar, the language recognized by the attribute grammar and the translation specified by the attribute grammar. The various definitions are compared with some alternative ones. Based on properties of the translation specified by an attribute grammar two new subclasses of attribute grammars are introduced: the determinate and the unambiguous attribute grammars. Furthermore the concept of an evaluator is considered. Based on properties of an evaluator for an attribute grammar some new subclasses of attribute grammars are introduced: the k-visit attribute grammars and the k left-to-right pass attribute grammars (k is an integer). It turns out that the k-visit as well as the k left-to-right pass attribute grammars define proper hierarchies of translations when some conditions are satisfied. It is also shown that there are translations specified by 1-visit anribute grammars that cannot be specified by any k left-to-right pass attribute grammar (when some conditions are satisfied). On the other hand it turns out that any well-defined attribute grammar is k-visit for some k.

Computational Learning of Syntax

Abstract: Learnability has traditionally been considered to be a crucial constraint on theoretical syntax; however, the issues involved have been poorly understood, partly as a result of the lack of simple learning algorithms for various types of formal grammars. Here I discuss the computational issues involved in learning hierarchically structured grammars from strings of symbols alone. The methods involved are based on an abstract notion of the derivational context of a syntactic category, which in the most elementary case of context-free grammars leads to learning algorithms based on a form of traditional distributional analysis. Crucially, these techniques can be extended to work with mildly context-sensitive grammars (and beyond), thus leading to learning methods that can in principle learn classes of grammars that are powerful enough to represent all natural languages. These learning methods require that the syntactic categories of the grammars be visible in a certain technical sense: They must be well charac...

On permutative grammars generating context-free languages

Abstract: A grammar is said to be permutative if it has permutation productions of the formAB ρBA in addition to context-free productions. Szilard languages and label languages are studied as examples of languages generable by permutative grammars. Particularly, sufficient conditions for a permutative grammar to generate a context-free language are studied.

Left-to-right parsing and bilexical context-free grammars

Abstract: We compare the asymptotic time complexity of left-to-right and bidirectional parsing techniques for bilexical context-free grammars, a grammar formalism that is an abstraction of language models used in several state-of-the-art real-world parsers. We provide evidence that left-to-right parsing cannot be realised within acceptable time-bounds if the so called correct-prefix property is to be ensured. Our evidence is based on complexity results for the representation of regular languages.