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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TL;DR: The survey at hand picks out important studies on learning indexed families of recursive languages (including basic as well as recent research), summarizes and illustrates the corresponding results, and points out links to related fields such as grammatical inference, machine learning, and artificial intelligence in general.
68 citations
TL;DR: This paper gives a progression of automata and shows that it corresponds exactly to the language hierarchy defined with control grammars, the first member of which is context-free languages.
63 citations
TL;DR: An infinite hierarchy of classes of languages is exhibited between the class of context-sensitive languages and the classof context-free languages.
Abstract: The class of languages expressible as the intersection ofk context-free languages is shown to be properly contained within the class of languages expressible as the intersection ofk + 1 context-free languages. Hence an infinite hierarchy of classes of languages is exhibited between the class of context-sensitive languages and the class of context-free languages.
63 citations
15 Oct 1973
TL;DR: A class of naturallanguage grammars is formalized and the sentence-recognition problem is shown to be polynomial-hard although the languages are context-sensitive, and new language-theoretic characterizations are given.
Abstract: Complexity of sentence recognition is studied for one-way stack languages, indexed languages, and tree transducer languages The problem is shown to be polynomial-complete in each case A class of naturallanguage grammars is formalized and the sentence-recognition problem is shown to be polynomial-hard although the languages are context-sensitive The proofs give new language-theoretic characterizations of the set of satisfiable propositional formulas and the set of prepositional tautologies
56 citations
27 Jun 2001
TL;DR: It is concluded that Minimalist Grammars are weakly equivalent to Multiple Context-Free Grammar.
Abstract: In this paper we will fix the position of Minimalist Grammars as defined in Stabler (1997) in the hierarchy of formal languages. Michaelis (1998) has shown that the set of languages generated by Minimalist Grammars is a subset of the set of languages generated by Multiple Context-Free Grammars (Seki et al., 1991). In this paper we will present a proof showing the reverse. We thus conclude that Minimalist Grammars are weakly equivalent to Multiple Context-Free Grammars.
56 citations