منابع مشابه
On the Complexity of Szilard Languages of Regulated Grammars
We investigate computational resources used by alternating Turing machines (ATMs) to accept Szilard languages (SZLs) of regulated rewriting grammars. The main goal is to relate these languages to lowlevel complexity classes such asNC1 andNC2. We focus on the derivation process in random context grammars (RCGs) with context-free rules. We prove that unrestricted SZLs and leftmost-1 SZLs of RCGs ...
متن کاملFormal Translations and Szilard Languages
One of the m e thods for def ining t ranslat ions is the so called syntax-di rec ted t rans la t ion scheme which can be in terpre ted as a pair of ra ther s imilar g rammars wi th the product ions work ing in parallel. Because of the s imilar i ty of the g r a m m a r s each of the two g rammars "f i ts" the other in the sense tha t for each der ivat ion process in one g r a m m a r leading to...
متن کاملRanking and Unranking Left Szilard Languages
We give efficient ranking and unranking algorithms for left Szilard languages of context-free grammars. If O(n2) time and space preprocessing is allowed then each ranking operation is possible in linear time. Unranking takes time O(n log n). These algorithms imply similar algorithms for context-free languages generated by arbitrary unambiguous context-free grammars.
متن کاملProbabilistic Grammars and Languages
A classic theorem of Ellis (1970) asserts that there are probabilistic languages (p-languages) that are not generated by any probabilistic finite state grammar (PFSG) even though their support (the set of strings with nonzero probability) is regular. Ellis’ proof is highly algebraic, and gives no indication why such p-languages exist. Suppes (1970) argued that Ellis’ construction is an artefact...
متن کاملSzilard Languages Associated to Parallel Communicating Grammar Systems
We associate Szilard and extended Szilard languages to parallel communicating grammar systems, starting from labels associated to productions of the components of the systems. We study families of such languages associated to various classes of parallel communicating grammar systems, comparing them to each other, to families of languages generated by regulated rewriting devices or by parallel c...
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ژورنال
عنوان ژورنال: Information and Control
سال: 1979
ISSN: 0019-9958
DOI: 10.1016/s0019-9958(79)90808-8