Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Relation between powers of factors and recurrence function
  characterizing Sturmian words   In this paper we use the relation of the index of an infinite aperiodic word
and its recurrence function to give another characterization of Sturmian words.
As a byproduct, we give a new proof of theorem describing the index of a
Sturmian word in terms of the continued fraction expansion of its slope. This
theorem was independently proved by Carpi and de Luca, and Damanik and Lenz.

16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
6
The categories of this paper are: astro-ph
26
The categories of this paper are: bayes-an
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg
4
The categories of this paper are: cond-mat
37
The categories of this paper are: supr-con
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int