Showing papers on "Indexed language published in 1980"
TL;DR: The main theorem is a result on the combinatorial structure of graph languages generated by NLC grammars; it resembles the pumping theorem for context-free string languages.
163 citations
TL;DR: The class of deterministic context-free languages is properly contained in the class of Deterministic indexed languages, which itself is properlycontained in theclass of indexed languages.
Abstract: A new type of acceptor is introduced for the class of indexed languages. The class of languages recognized by the deterministic version of this acceptor, called deterministic indexed languages, is closed under complemention. The class of deterministic context-free languages is properly contained in the class of deterministic indexed languages, which itself is properly contained in the class of indexed languages.
19 citations
01 Jan 1980
TL;DR: The chapter explains that there are deficiencies in the theory of automata and the deficiencies are reparable and the automata are so much more complicated that they would be used in formal proofs only with great awkwardness and when a proof by means of grammars is for some reason not feasible.
Abstract: Publisher Summary This chapter discusses the relationship between formal languages and automata. The relationship is a weak one and proceeds in only one direction. Automata are used as acceptors to define languages; therefore, the languages can be considered the external behavior of their acceptors and that end the relationship. There is no application of results from language theory to the study of automata. The chapter explains that there are deficiencies in the theory of automata and the deficiencies are reparable. The automata may be more intuitive than that of grammars; however, automata are so much more complicated that they would be used in formal proofs only with great awkwardness and when a proof by means of grammars is for some reason not feasible. A finite-state automaton is not always the best way to describe a regular set. There is no single method of representing regular sets that is always the most convenient to use.
13 citations
TL;DR: It is shown that the family of all linear grammars with a fixed ratio between the sizes of the terminal strings on both sides of the nonterminal in a right-hand side of production has a decidable equivalence problem.
Abstract: It is shown that the family of all linear grammars with a fixed ratio between the sizes of the terminal strings on both sides of the nonterminal in a right-hand side of production (which we call uniform linear grammars) has a decidable equivalence problem. The corresponding language family is properly contained in the linear unambiguous context-free languages and contains some nondeterministic languages.
6 citations
TL;DR: The class of deterministic indexed languages will be further investigated and a number of closure and non-closure results are presented, which have an analogon in the theory of Deterministic context-free languages.
Abstract: The class of deterministic indexed languages will be further investigated. A number of closure and non-closure results are presented. All this results have an analogon in the theory of deterministic context-free languages.
5 citations