Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A short note on reduced residues   We solve a problem due to Recam\'an about the lower bound behavior of the
maximum possible length among all arithmetic progressions in the least reduced
residue system modulo $n$, as $n \to \infty$.

23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
15
The categories of this paper are: nucl-ex
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg