Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Grand Unification from Gauge Theory on $M_4 \times Z_N$   The SU(5) grand unified theory (GUT) is derived from the geometrical point of
view of gauge theory on three-sheeted space-time, i.e., $M_4 \times Z_3$
manifold without recourse to noncommutative geometry. A derivation of SO(10)
GUT is also discussed in the same point of view.

16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
9
The categories of this paper are: nlin
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th