Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Flipping SU(5) Towards Five Dimensional Unification   It is shown that embedding of flipped SU(5) in a five-dimensional SO(10)
enables exact unification of the gauge coupling constants. The demand for the
unification uniquely determines both the compactification scale and the cutoff
scale. These are found to be 5.5 \times 10^{14} GeV and 1.0 \times 10^{17} GeV
respectively. The theory explains the absence of d=5 proton-decay operators
through the implementation of the missing partner mechanism. On the other hand,
the presence of d=6 proton-decay operators points towards the bulk localization
of the first and the second family of matter fields.

30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
6
The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg