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 کاملThe Free AMPLE Monoid
We show that the free weakly E-ample monoid on a set X is a full submonoid of the free inverse monoid FIM(X) on X . Consequently, it is ample, and so coincides with both the free weakly ample and the free ample monoid FAM(X) on X . We introduce the notion of a semidirect product Y ∗ T of a monoid T acting doubly on a semilattice Y with identity. We argue that the free monoid X∗ acts doubly on t...
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Given positive integers c1, c2, . . . , ck with gcd(c1, c2, . . . , ck) = 1, the Frobenius problem (FP) is to compute the largest integer g(c1, c2, . . . , ck) that cannot be written as a non-negative integer linear combination of c1, c2, . . . , ck. The Frobenius problem in a free monoid (FPFM) is a non-commutative generalization of the Frobenius problem. Given words x1, x2, . . . , xk such th...
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In this paper we prove a conjecture stated in an earlier paper [ A-L]]. The conjecture states that with respect to a rather natural operation, the set of N -dimensional magic cubes forms a free monoid for every integer N > 1. A consequence of this conjecture is a certain identity of formal Dirichlet series. These series and the associated power series are shown to diverge. Generalizations of th...
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 1982
ISSN: 0304-3975
DOI: 10.1016/0304-3975(82)90070-6