منابع مشابه
Hierarchies of Hyper-AFLs
For a full semi-AFL K, B(K) is defined as the family of languages generated by all K-extended basic macro grammars, while H(K) 5 B(K) is the smallest full hyper-AFL containing K, a full basic-AFL is a full AFL K such that B(K) = K (hence every full basic-AFL is a full hyper-AFL). For any full semi-AFL K, K is a full basic-AFL if and only if B(K) is substitution closed if and only if H(K) is a f...
متن کاملOn ET0L Systems of Finite Index
The theory of L systems (see, e.g., Herman and Rozenberg (1975) and Rozenberg and Salomaa (1974, 1976)) constitutes today one of the most pursued fragments of formal language theory. Its relevance to the formal language theory stems from the facts that it introduced new range of problems and proof techniques and has put some of the old concepts and problems in a better perspective. In this pape...
متن کاملRemarks on Propagating Partition-limited Et0l Systems
In this paper, we sharpen the results of GG artner on the universality of partition-limited ET0L systems by showing that such deterministic systems characterize the recursively enumerable sets, and, furthermore, the propagating deterministic partition-limited ET0L systems characterize the programmed languages with appearance checking disallowing erasing productions. The main results of this pap...
متن کاملConditional Tabled Eco-grammar Systems versus Et0l Systems
We i n vestigate the generative capacity of the so-called conditional tabled eco-grammar systems CTEG. They are a variant of eco-grammar systems, generative mechanisms recently introduced as models of the interplay b e t ween environment and agents in ecosystems. In particular, we compare the power of CTEG systems with that of programmed and of random context T0L systems and with that of ET0L s...
متن کاملSimple Semi-conditional Et0l Grammars
The present contribution introduces and studies simple semi-conditional ET0L grammars (SSC-ET0L grammars for short). It is demonstrated that SSC-ET0L grammars with permitting and forbidding conditions of length no more than one and two, respectively, generate all the family of recursively enumerable languages; if erasing productions are not allowed, these grammars generate precisely the family ...
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ژورنال
عنوان ژورنال: DAIMI Report Series
سال: 1974
ISSN: 2245-9316,0105-8517
DOI: 10.7146/dpb.v3i35.6456