منابع مشابه
The 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...
متن کاملThe Frobenius Problem in a Free Monoid
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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A congruence p on a free monoid X* is said to be infix if each class C of p satisfies u e C and xuy € C imply xy = 1 . The main purpose of this paper is a characterization of commutative maximal infix congruences. These turn out to be congruences induced by homomorphisms t from X* to N° , the monoid of nonnegative integers under addition, with T"1(0) = 1.
متن کاملMagic N-Cubes Form a Free Monoid
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...
متن کاملPerfect Congruences on a Free Monoid
Perfect congruences on a free monoid X* are characterized in terms of congruences generated by partitions of X U {1}. It is established that the upper semilattice of perfect congruences if V-isomorphic to the upper semilattice of partitions on Xu{1}. A sublattice of the upper semilattice of perfect congruences is proved to be lattice isomorphic to the lattice of partitions on X. Introduction an...
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 1994
ISSN: 0304-3975
DOI: 10.1016/0304-3975(94)90274-7