منابع مشابه
Bounded Counter Languages
We show that deterministic finite automata equipped with k two-way heads are equivalent to deterministic machines with a single two-way input head and k− 1 linearly bounded counters if the accepted language is strictly bounded, i.e., a subset of a∗1a ∗ 2 · · · a ∗ m for a fixed sequence of symbols a1, a2, . . . , am. Then we investigate linear speed-up for counter machines. Lower and upper time...
متن کاملScope-Bounded Pushdown Languages
We study the formal language theory of multistack pushdown automata (Mpa) restricted to computations where a symbol can be popped from a stack S only if it was pushed within a bounded number of contexts of S (scoped Mpa). We show that scoped Mpa are indeed a robust model of computation, by focusing on the corresponding theory of visibly Mpa (Mvpa). We prove the equivalence of the deterministic ...
متن کاملDerivation Languages of Graph Grammars
We investigate sequential derivation languages associated with graph grammars, as a loose generalisation of free-labeled Petri nets and Szilard languages. The grammars are used to output strings of rule labels, and the applicability of a special rule determines the acceptance of a preceding derivation. Due to the great power of such grammars, this family of languages is quite large and endowed ...
متن کاملOn Reversal-Bounded Picture Languages
Kim, C. and I.H. Sudborough, On reversal-bounded picture languages, Theoretical Computer Science 104 (1992) 185-206. For an integer k >O, a k-reversal-bounded picture language is a chain-code picture language which is described by a language L over the alphabet R= {u,d,r, I} such that, for every word x in L, the number of alternating occurrences of r’s and I’s in x is bounded by k. It is shown ...
متن کاملBounded repairability of word languages
What do you do if a computational object (e.g. program trace) fails a specification? An obvious approach is to perform a repair : modify the object minimally to get something that satisfies the constraints. This approach has been investigated in the database community, for integrity constraints, and in the AI community for propositional logics. Here we study how difficult it is to repair a docu...
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ژورنال
عنوان ژورنال: Journal of Computer and System Sciences
سال: 1968
ISSN: 0022-0000
DOI: 10.1016/s0022-0000(68)80009-1