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 study grand unified theories based on an SU(5)xSU(5) gauge group in which
the GUT scale, M_{GUT}, is the VEV of an exact or approximate modulus, and in
which fast proton decay is avoided through a combination of a large triplet
mass and small triplet couplings. These features are achieved by discrete
symmetries. In many of our models, M_{GUT} is generated naturally by the
balance of higher dimension terms that lift the GUT modulus potential, and soft
supersymmetry breaking masses. The theories often lead to interesting patterns
of quark and lepton masses. We also discuss some distinctions between grand
unified theories and string unification.

23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
6
The categories of this paper are: astro-ph
1
The categories of this paper are: cs