Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Product Groups, Discrete Symmetries, and Grand Unification   We present GUT models based on an $SU(5)\times SU(5)$ GUT group. These models
maintain the main successes of simple-group GUTs but permit simple solutions to
the doublet-triplet splitting problem. Moreover, GUT breaking is triggered by
supersymmetry breaking so that the GUT scale is naturally generated as a
combination of the Planck scale and the supersymmetry breaking scale.

13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
17
The categories of this paper are: q-fin
2
The categories of this paper are: math
6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
4
The categories of this paper are: cond-mat
15
The categories of this paper are: nucl-ex