Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Inverse eigenvalues problem of nonnegative matrices via unit lower
  triangular matrices   The main of this work is to use the unit lower triangular matrices for
solving inverse eigenvalue problem of nonnegative matrices and present the
easier method to solve this problem.

31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
6
The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
37
The categories of this paper are: supr-con
21
The categories of this paper are: adap-org
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th