On gapped repeats in a cyclic Fibonacci word
2026-06-01 • Formal Languages and Automata Theory
Formal Languages and Automata Theory
AI summaryⓘ
The authors study how certain sequences of letters called words match up when you look at parts of them starting from different positions in a looped way (cyclic indices). They focus on the special Fibonacci word, which is built using a pattern related to the Fibonacci numbers. They figure out exactly when two starting points produce the same sequence of letters of a certain length. They also count how many such matching pairs exist within this cyclic Fibonacci word.
cyclic indicesFibonacci wordword combinatoricsstring matchingsequence repetitionindex pairscombinatorics on wordscyclic wordsabstract algebra
Authors
Takashi Horiyama, Yasuhide Numata, Kazuhisa Seto, Shuhei Tsujie
Abstract
In this article, we consider the words with cyclic indices. For given $s$, we consider the pair $(ι,κ)$ of indices such that the word of length $s$ from $ι$ is equal to the word of length $s$ from $κ$. We give a characterization of such pairs for a cyclic Fibonacci word, and give the number of them.