Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Estimation of positive definite M-matrices and structure learning for
  attractive Gaussian Markov Random fields
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
21
The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin