Bell and Shallit recently introduced the Lie complexity of an infinite word $s$ as the function counting for each length the number of conjugacy classes of words whose elements are all factors of $s$. They proved, using algebraic techniques, that the Lie complexity is bounded above by the first difference of the factor complexity plus one; hence, it is uniformly bounded for words with linear factor complexity, and, in particular, it is at most 2 for Sturmian words, which are precisely the words with factor complexity $n+1$ for every $n$. In this note, we provide an elementary combinatorial proof of the result of Bell and Shallit and give an exact formula for the Lie complexity of any Sturmian word.
翻译:Bell and Shalit最近引入了无限字数的复杂性。 字数是无限的字数, 以每长的字数计算。 它们用代数技术证明, 字数的复杂性比因素复杂度的第一个差异加一个, 因此, 字数与线性因素复杂度一致, 特别是, Sturmian 字数最多是两个, 也就是每美元中每个字的复数, 也就是每美元中具有要素复杂性的字数。 在本说明中, 我们提供了Bell 和 Shalit 的结果的基本组合证明, 并为任何Sturmian 字的精度复杂性给出了精确的公式 。