منابع مشابه
Deciding Piecewise Testable Separability for Regular Tree Languages
The piecewise testable separability problem asks, given two input languages, whether there exists a piecewise testable language that contains the first input language and is disjoint from the second. We prove a general characterisation of piecewise testable separability on languages in a well-quasiorder, in terms of ideals of the ordering. This subsumes the known characterisations in the case o...
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 کاملAlternative Automata Characterization of Piecewise Testable Languages
We present a transparent condition on a minimal automaton which is equivalent to piecewise testability of the corresponding regular language. The condition simplifies the original Simon’s condition on the minimal automaton in a different way than conditions of Stern and Trahtman. Secondly, we prove that every piecewise testable language L is k-piecewise testable for k equal to the depth of the ...
متن کاملPiecewise Testable Languages and Nondeterministic Automata
A regular language is k-piecewise testable if it is a finite boolean combination of languages of the form Σa1Σ · · ·ΣanΣ, where ai ∈ Σ and 0 ≤ n ≤ k. Given a DFA A and k ≥ 0, it is an NLcomplete problem to decide whether the language L(A) is piecewise testable and, for k ≥ 4, it is coNP-complete to decide whether the language L(A) is k-piecewise testable. It is known that the depth of the minim...
متن کاملPiecewise testable languages via combinatorics on words
A regular language L over an alphabet A is called piecewise testable if it is a finite boolean combination of languages of the form Aa1A a2A ∗ . . . Aa`A ∗, where a1, . . . , a` ∈ A, ` ≥ 0. An effective characterization of piecewise testable languages was given in 1972 by Simon who proved that a language L is piecewise testable if and only if its syntactic monoid is J -trivial. Nowadays there e...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Logical Methods in Computer Science
سال: 2012
ISSN: 1860-5974
DOI: 10.2168/lmcs-8(3:26)2012