Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Characterization of preorders induced by positive maps in the set of
  Hermitian matrices
16
The categories of this paper are: stat
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph