Topic
Indexed language
About: Indexed language is a research topic. Over the lifetime, 334 publications have been published within this topic receiving 11000 citations.
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16 Jul 2003
TL;DR: By slightly restricting the operation of the machine, a bottom-up parser is obtained which operates by reducing instances of the right-hand side of productions in a sentencial form to the corresponding left- hand side and the resulting devices are indeed context-sensitive parsers.
Abstract: In this work we propose a method to derive Stack Automata [1] from context-free grammars with regular control languages [3]; by slightly restricting the operation of the machine we obtain a bottom-up parser which operates by reducing instances of the right-hand side of productions in a sentencial form to the corresponding left-hand side; since context-free grammars with regular control languages are Turing powerful and Stack Automata accept, at least, context-sensitive languages [2], the resulting devices are indeed context-sensitive parsers.
2 citations
TL;DR: It is shown that, given a right linear or a strongLL(k) grammar, it is possible to produce automatically a pointer Markov algorithm parsing the language generated by the grammar.
Abstract: Markov algorithms have received very little attention in the studies about formal languages, so the purpose of the present paper is twofold: i) to characterize languages in terms of Markov algorithms, and ii) to produce automatically Markov algorithms accepting or parsing languages generated by given grammars.
2 citations
TL;DR: A family of context-free languages that reduce to e in the free group and give several homomorphic characterizations of indexed languages relevant to that family are studied.
Abstract: We study a family of context-free languages that reduce to e in the free group and give several homomorphic characterizations of indexed languages relevant to that family.
2 citations
DOI•
01 May 2000
TL;DR: It can be shown that the resulting formalisms give rise to a hierarchy of languages that is equivale nt with a hierarchy defined by Weir, and since all languages of Weir’s hierarchy e known to be mildly context sensitive, the proposed extensions of LIGs become comparabl e with extensions of tree adjoining Grammars and head grammars.
Abstract: This paper presents a possibility to extend the formalism of linear indexed grammars. The extension is based on the use of tuples of pushdowns instead of one pushdown to store indices during a derivation. If a restriction on the accessibility of the pushdowns is used, it can be shown that the resulting formalisms give rise to a hierarchy of languages that is equivalent with a hierarchy defined by Weir. For this equivalence, that was already known for a slightly different formalism, this paper gives a new proof. Since all languages of Weir's hierarchy are known to be mildly context sensitive, the proposed extensions of LIGs become comparable with extensions of tree adjoining grammars and head grammars.
2 citations