Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Phase stability, chemical bonding and mechanical properties of titanium
  nitrides: A first-principles study
8
The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
23
The categories of this paper are: solv-int
6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
25
The categories of this paper are: patt-sol
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci