Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: On existence of certain error formulas for a special class of ideal
  projectors
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
14
The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
20
The categories of this paper are: acc-phys
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
26
The categories of this paper are: bayes-an
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
6
The categories of this paper are: astro-ph
11
The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph