Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: The $\omega$-limit set of a flow with arbitrarily many singular points
  on a surface and surgeries to add singular points
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph
4
The categories of this paper are: cond-mat
6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
19
The categories of this paper are: eess
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th