Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A complete characterization of graphs with exactly two positive
  eigenvalues   In 1977 Smith characterized graphs with exactly one positive eigenvalue.
Since then, many particular results related to graphs with exactly two positive
eigenvalues have emerged. In this paper we conclude this investigation by
giving a full characterization of these graphs.

29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat
22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th