Morphic words are letter-to-letter images of fixed points x of morphisms on finite alphabets. There are situations where these letter-to-letter maps do not occur naturally, but have to be replaced by a morphism. We call this a decoration of x. Theoretically, decorations of morphic words are again morphic words, but in several problems the idea of decorating the fixed point of a morphism is useful. We present two of such problems. The first considers the so called AA sequences, where α is a quadratic irrational, A is the Beatty sequence defined by A(n)=⌊αn⌋, and AA is the sequence (A(A(n))). The second example considers homomorphic embeddings of the Fibonacci language into the integers, which turns out to lead to generalized Beatty sequences with terms of the form V(n)=p⌊αn⌋+qn+r, where p,q and r are integers.

Original languageEnglish
Pages (from-to)407-417
Number of pages11
JournalTheoretical Computer Science
Publication statusPublished - 2020

    Research areas

  • Frobenius problem, Golden mean language, HD0L-system, Iterated Beatty sequence, Morphic word

ID: 68750724