Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: A short noncomplex proof for the solution set of homogeneous second
  order linear differential equations with constant coefficients
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat
1
The categories of this paper are: cs
4
The categories of this paper are: cond-mat
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc