Test sets for context free languages and algebraic systems of equations over a free monoid
نویسندگان
چکیده
منابع مشابه
Test Sets for Context Free Languages and Algebraic Systems of Equations over a Free Monoid
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...
متن کاملOptimal 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 2007 Kambites presented an algebraic interpretation of Chomsky-Schützenberger theorem for context-free languages. We give an interpretation of the corresponding theorem for the class of displacement context-free languages which are equivalent to well-nested multiple context-free languages. We also obtain a characterization of kdisplacement context-free languages in terms of monoid automata a...
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We show that, given an equation over a finitely generated free group, the set of all solutions in reduced words forms an effectively constructible EDT0L language. Thus, for each equation there is a construction of a Lindenmayer system which generates all solutions in reduced words. In particular, the set of all solutions in reduced words is an indexed language in the sense of Aho. The language ...
متن کاملOne Variable Equations in Free Groups via Context Free Languages
We use context free languages to analyze solution sets to one variable equations over free groups.
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ژورنال
عنوان ژورنال: Information and Control
سال: 1982
ISSN: 0019-9958
DOI: 10.1016/s0019-9958(82)80028-4