The task Task: Map a finite string α over an infinite alphabet onto a finite word w over a binary alphabet such that w reflects the structure of α "optimally".
[FRS06] characterises strings with an unambiguous image of an nonerasing morphism. Only few results are known when regarding all (possibly erasing) morphisms.
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… (More)