Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Palindromes and periodic continued fractions   This paper is devoted to a detailed exposition of geometry of continued
fractions. We pay particular interest to the case of quadratic irrationalities
and use the technique described to prove a criterion for the continued fraction
of a quadratic surd to have a symmetric period.

31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
14
The categories of this paper are: math-ph
4
The categories of this paper are: cond-mat
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
19
The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin