Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: User Cooperation for Enhanced Throughput Fairness in Wireless Powered
  Communication Networks
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
8
The categories of this paper are: hep-ex
19
The categories of this paper are: eess
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom
6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex