Journal ArticleDOI
On the emptiness of the intersection of two DOS languages problem
TLDR
The notion of a DOS system is introduced which is a ‘sequential counterpart of the idea of a DOL system l’ and it is proved that the emptiness of the intersection problem for two DOS systems is proved.About:
This article is published in Information Processing Letters.The article was published on 1980-07-05. It has received 7 citations till now. The article focuses on the topics: Intersection & Cone (formal languages).read more
Citations
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Very special languages and representations of recursively enumerable languages via computation histories
David Haussler,H. Paul Zeiger +1 more
TL;DR: In particular, the authors showed that any recursively enumerable language K ⊂ Σ* can be represented as K = Φ Σ (R ∩ D 1 ⋮ D 2 ), where R is a regular language depending on K and Φ is a weak identity homomorphism.
Journal ArticleDOI
On basic properties of DOS systems and languages
TL;DR: A new type of grammar called a DOS system is introduced and investigated, which formalizes the notion of a context free grammar without variables that is generatively deterministic.
Journal ArticleDOI
The undecidability of a word problem: On a conjecture of strong, Maggiolo-Schettini and Rosen☆
Journal ArticleDOI
Representation theorems using DOS languages
TL;DR: It is demonstrated that every context-free language is a homomorphic image of the intersection of two DOS languages and that every recursively enumerable language is the homomorphic images of the intersections of three DOS languages.
References
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Journal ArticleDOI
Simplifications of homomorphisms
TL;DR: The notion of a simplification of a homomorphism is introduced and investigated, and its usefulness is demonstrated in providing rather short proofs of the following results.