Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Natural R Parity Conservation with Horizontal Symmetries. a Four
  Generation Model
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg
4
The categories of this paper are: cond-mat
23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol