منابع مشابه
Morphically Primitive Words (extended Abstract) *
In the present paper, we introduce an alternative notion of the primitivity of words, that – unlike the standard understanding of this term – is not based on the power (and, hence, the concatenation) of words, but on morphisms. For any alphabet Σ, we call a word w ∈ Σ∗ morphically imprimitive provided that there are a shorter word v and morphisms h, h′ : Σ∗ → Σ∗ satisfying h(v) = w and h′(w) = ...
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Primitive words, or strings over a finite alphabet that cannot be written as a power of another string, play an important role in formal language theory, coding theory, and combinatorics on words to name a few. In this paper, we extend some fundamental results about primitive words to primitive partial words. Partial words are strings that may have a number of “do not know” symbols. © 2005 Else...
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We investigate Abelian primitive words, which are words that are not Abelian powers. We show the set of Abelian primitive words is not context-free. We can determine whether a word is Abelian primitive in linear time. Also different from classical primitive words, we find that a word may have more than one Abelian root. We also consider enumeration of Abelian primitive words.
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In this paper we count the number of abelian-primitive partial words of a given length over a given alphabet size, which are partial words that are not abelian powers. Partial words are sequences that may have undefined positions called holes. This combinatorial problem was considered recently for full words (those without holes). It turns out that, even for the full word case, it is a nontrivi...
متن کاملCounting Primitive Partial Words
A word is primitive if it is not a power of another word. The number of primitive words of a fixed length over an alphabet of a fixed size is well known and relates to the Möbius function. In this paper, we investigate the number of primitive partial words which are strings that may contain “do not know” symbols.
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 2009
ISSN: 0304-3975
DOI: 10.1016/j.tcs.2009.01.020