Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: X-ray pulse generation with ultra-fast flipping of its orbital angular
  momentum
11
The categories of this paper are: hep-lat
2
The categories of this paper are: math
19
The categories of this paper are: eess
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph
7
The categories of this paper are: hep-th
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex