منابع مشابه
Complexity of testing morphic primitivity
The word u = abaaba satisfies f(u) = u where f maps b to aba and cancels a. Such words, which are fixed points of a nontrivial morphism, are called morphically imprimitive. On the other hand, the word u′ = abba can be easily verified to be morphically primitive, which means that the only morphism satisfying f(u′) = u′ defined on {a, b}∗ is the identity. Fixed points of word morphisms and morphi...
متن کاملMorphic Primitivity and Alphabet Reductions
An alphabet reduction is a 1-uniform morphism that maps a word to an image that contains a smaller number of different letters. In the present paper we investigate the effect of alphabet reductions on morphically primitive words, i. e., words that are not a fixed point of a nontrivial morphism. Our first main result answers a question on the existence of unambiguous alphabet reductions for such...
متن کاملOn the Primitivity of SPARQL 1.1 Operators
The paper studies the primitivity of the eleven basic operators used in the SPARQL 1.1 query language. This paper shows that the six operators BIND, FILTER, GRAPH, property path, SELECT, and VALUES are primitive while the left five operators AND, EXISTS, MINUS, OPT, and UNION, are not primitive. It is surprised that OPT and UNION which are primitive in SPARQL 1.0 become no longer primitive in S...
متن کاملOn the primitivity of operators in SPARQL
The paper studies the primitivity of the basic operators UNION, AND, OPTIONAL, FILTER, and SELECT, as they are used in the SPARQL query language. The question of whether one operator can be expressed in terms of the other operators is answered in detail. It turns out that only AND is non-primitive. These results are shown to be insensitive to the choice of semantics for filter conditions (three...
متن کاملOn the Primitivity of some Trinomials over Finite Fields
In this paper, we give conditions under which the trinomials of the form x + ax + b over finite field Fpm are not primitive and conditions under which there are no primitive trinomials of the form x +ax+b over finite field Fpm . For finite field F4, We show that there are no primitive trinomials of the form x + x + α, if n ≡ 1 mod 3 or n ≡ 0 mod 3 or n ≡ 4 mod 5.
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ژورنال
عنوان ژورنال: Journal of Pure and Applied Algebra
سال: 1986
ISSN: 0022-4049
DOI: 10.1016/0022-4049(86)90070-8