منابع مشابه
On Decidability of Hierarchies of Regular Aperiodic Languages
In automata theory, several natural hierarchies of regular languages are studied. Among the most popular are hierarchies of Brzozowski and Straubing (see e.g [11]), both exhausting the class of so called regular aperiodic (or star–free) languages. A natural question about these hierarchies is formulated as follows: given a level of a hierarchy and a finite automaton, one has to decide effective...
متن کاملAperiodic languages and generalizations.dvi
For every integer k ≥ 0, a class of languages, called kaperiodic languages, is defined, generalizing the class of aperiodic languages. Properties of these classes are investigated, in particular the operations under which they are preserved. A characterization of the syntactic monoid of a kaperiodic language is also obtained.
متن کاملHierarchies of Piecewise Testable Languages
The classes of languages which are boolean combinations of languages of the form Aa1A a2A ∗ . . . Aa`A , where a1, . . . , a` ∈ A, ` ≤ k , for a fixed k ≥ 0, form a natural hierarchy within piecewise testable languages and have been studied in papers by Simon, Blanchet-Sadri, Volkov and others. The main issues were the existence of finite bases of identities for the corresponding pseudovarietie...
متن کاملSome Uncountable Hierarchies of Formal Languages
We consider several types of similarity relationships between languages, and for an arbitrary language class we define appropriate similarity classes. We show that for any of the classes of regular, linear, contextfree, context-sensitive, recursive and recursively enumerable languages the appropriate similarity classes form an uncountable hierarchy of order type ω + λ + 2. We also show that the...
متن کاملM . Baclet Logical Characterization of Aperiodic Data Languages
Data languages are an extension of timed languages, as defined by R. Alur and D. L. Dill, proposed by P. Bouyer, A. Petit and D. Thérien to provide a suitable theoretical framework, comparable to the formal languages theory. A class of data languages, naturally called recognizable data languages, can be defined in an equivalent way by automata, finite monoids and logic formulas. The aim of this...
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ژورنال
عنوان ژورنال: Revue française d'automatique informatique recherche opérationnelle. Informatique théorique
سال: 1976
ISSN: 0397-9326
DOI: 10.1051/ita/197610r200331