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.

Distributional learning of parallel multiple context-free grammars

Abstract: Natural languages require grammars beyond context-free for their description. Here we extend a family of distributional learning algorithms for context-free grammars to the class of Parallel Multiple Context-Free Grammars (pmcfgs). These grammars have two additional operations beyond the simple context-free operation of concatenation: the ability to interleave strings of symbols, and the ability to copy or duplicate strings. This allows the grammars to generate some non-semilinear languages, which are outside the class of mildly context-sensitive grammars. These grammars, if augmented with a suitable feature mechanism, are capable of representing all of the syntactic phenomena that have been claimed to exist in natural language. We present a learning algorithm for a large subclass of these grammars, that includes all regular languages but not all context-free languages. This algorithm relies on a generalisation of the notion of distribution as a function from tuples of strings to entire sentences; we define nonterminals using finite sets of these functions. Our learning algorithm uses a nonprobabilistic learning paradigm which allows for membership queries as well as positive samples; it runs in polynomial time.

A characterization of context-free string languages by directed node-label controlled graph grammars

Abstract: Directed node-label controlled graph grammars (DNLC grammars) are sequential graph rewriting systems. In a direct derivation step of a DNLC grammar a single node is rewritten. Both the rewriting of a node and the embedding of a "daughter graph" in a "host graph" are controlled by the labels of nodes only. We study the use of those grammars to define string languages. In particular we provide a characterization of the class of context-free string languages in terms of DNLC grammars.

Finite-State Approximation of Phrase-Structure Grammars

Abstract: This chapter contains sections titled: Motivation, The Approximation Method, Formal Properties, Implementation and Example, Informal Analysis, Related Work and Conclusions, Appendix—APSG formalism and example, Acknowledgments, References

A Bootstrap Method for Constructing Local Grammars

Abstract: Local grammars are finite-state grammars or finite-state automata that represent sets of utterances of a natural language. Local grammars have been used to describe a wide variety of sets of strings, ranging from finite sets of words related by prefixation and suffixation to sets of sentences syntactically and semantically related. Formal representations of finite-state grammars are quite varied, although equivalent. We have chosen a particular representation by graphs which is well-adapted to the syntax of natural languages. Using a particular example, we will present in detail a method for constructing local grammars using large corpora.