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 inclusion problem between the frontier language of a non-deterministic recursive program scheme and the Dyck language is considered, and it is proved that it is undecidable by a reduction from the undecidability of Hilbert's 10th problem.
8 citations
03 May 1971
TL;DR: Absolutely parallel grammars are defined and it is shown that the family of languages generated is equal to the familyof languages generated by two-way deterministic finite-state transducers.
Abstract: Absolutely parallel grammars are defined and it is shown that the family of languages generated is equal to the family of languages generated by two-way deterministic finite-state transducers. Furthermore it is shown that this family forms a full AFL [4], is properly contained in the family of languages generated by two-way nondeterministic finite-state transducers (which is equal to the family of checking automata languages [8]) and properly contains the family of nonexpansive context-free languages [7].
7 citations
28 May 2014
TL;DR: A new variant of P2DCFGs that generates picture arrays in a leftmost way is introduced that examines the power of these generators that regulate rewriting by control languages.
Abstract: Considering a large variety of approaches in generating picture languages, the notion of pure two-dimensional context-free grammar P2DCFG represents a simple yet expressive non-isometric language generator of picture arrays. In the present paper, we introduce a new variant of P2DCFGs that generates picture arrays in a leftmost way. We concentrate our attention on determining their generative power by comparing it with the power of other picture generators. We also examine the power of these generators that regulate rewriting by control languages.
7 citations
TL;DR: Two new classes of generative grammars are defined and the generative power of compound and serial Grammars consisting of finite-state grammARS is investigated.
Abstract: Two new classes of generative grammars are defined. The first class, the compound grammars, consists of grammars in which the initial symbol is replaced by the language generated by another grammar. The other class, the serial grammars, consists of sequences of compound grammars. The generative power of compound and serial grammars consisting of finite-state grammars is investigated.
7 citations
TL;DR: BD (Breadth-Depth) grammars are introduced which extend context-free Grammars by allowing breadth-first derivations and are recognized by Deque (double ended queue) automata having a sin...
Abstract: We introduce BD (Breadth-Depth) grammars which extend context-free grammars by allowing breadth-first derivations. Their languages are recognized by Deque (double ended queue) automata having a sin...
7 citations