Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Spectra and evolution of two X-ray sources in M81
21
The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
2
The categories of this paper are: math
9
The categories of this paper are: nlin
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
1
The categories of this paper are: cs