منابع مشابه
Weakly Unambiguous Morphisms
A nonerasing morphism σ is said to be weakly unambiguous with respect to a word s if σ is the only nonerasing morphism that can map s to σ(s), i. e., there does not exist any other nonerasing morphism τ satisfying τ(s) = σ(s). In the present paper, we wish to characterise those words with respect to which there exists such a morphism. This question is nontrivial if we consider so-called length-...
متن کاملUnambiguous 1-uniform morphisms
If, for a morphism σ : ∆∗ → Σ∗ (where ∆ and Σ are arbitrary alphabets) and a word α ∈ ∆∗, there exists another morphism τ mapping α to σ(α), then σ is called ambiguous with respect to α ; if such a τ does not exist, then σ is unambiguous. For example, the morphism σ0 : {A,B,C}∗ → {a,b}∗ – given by σ0(A) := a, σ0(B) := a, σ0(C) := b – is ambiguous with respect to the word α0 := ABCACB, since the...
متن کاملWeakly Unambiguous Morphisms with Respect to Sets of Patterns with Constants
A non-erasing morphism is weakly unambiguous with respect to a pattern if no other non-erasing morphism maps the pattern to the same image. If the size of the target alphabet is at least three, then the patterns for which there exists a length-increasing weakly unambiguous morphism can be characterized using the concept of loyal neighbors of variables. In this article this characterization is g...
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[FRS06] characterises strings with an unambiguous image of an nonerasing morphism. Only few results are known when regarding all (possibly erasing) morphisms.
متن کاملOperations on Weakly Recognizing Morphisms
Weakly recognizing morphisms from free semigroups onto finite semigroups are a classical way for defining the class of ω-regular languages, i.e., a set of infinite words is weakly recognizable by such a morphism if and only if it is accepted by some Büchi automaton. We consider the descriptional complexity of various constructions for weakly recognizing morphisms. This includes the conversion f...
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 2012
ISSN: 0304-3975
DOI: 10.1016/j.tcs.2012.04.045