Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: No Community Can Do Everything: Why People Participate in Similar Online
  Communities
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph