Efficient constructions of test sets for regular and context-free languages
نویسندگان
چکیده
منابع مشابه
Optimal Test Sets for Context-Free Languages
A test set for a formal language (set of strings) L is a subset T of L such that for any two string homomorphisms f and g defined on L, if the restrictions of f and g on T are identical functions, then f and g are identical on the entire L. Previously, it was shown that there are context-free grammars for which smallest test sets are cubic in the size of the grammar, which gives a lower bound o...
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In this paper we consider two questions. First we consider whether every pattern language which is regular can be generated by a regular pattern. We show that this is indeed the case for extended (erasing) pattern languages if alphabet size is at least four. In all other cases, we show that there are patterns generating a regular language which cannot be generated by a regular pattern. Next we ...
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Muller context-free languages (MCFLs) are languages of countable words, that is, labeled countable linear orders, generated by Muller context-free grammars. Equivalently, they are the frontier languages of (nondeterministic Muller-)regular languages of infinite trees. In this article we survey the known results regarding MCFLs, and show that a language is an MCFL if and only if it can be genera...
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We investigate regular realizability (RR) problems, which are the problems of verifying whether the intersection of a regular language – the input of the problem – and a fixed language, called a filter, is non-empty. In this paper we focus on the case of context-free filters. The algorithmic complexity of the RR problem is a very coarse measure of the complexity of context-free languages. This ...
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It is shown that for every context free language L there effectively exists a test set F, that is, a finite subset F of L such that, for any pair (g, h) of morphisms, g(x) = h(x) for all x in F implies g(x) = h(x) for all x in L. This result was claimed earlier but a detailed correct proof is given here. Together with very recent results on systems of equations over a free monoid this result im...
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 1993
ISSN: 0304-3975
DOI: 10.1016/0304-3975(93)90325-n