Grand Unification from Gauge Theory on $M_4\times Z_N$

Abstract

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.

11 pages, 7 figures, style changed to revtex, added reference to section 1, corrected typos