Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Pointwise approximation of functions by matrix operators of their
  Fourier series with $r$- differences of the entries
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph