Flipped SO(10) model

We show that as in the flipped SU(5) models, doublet-triplet splitting is realized by the missing partner mechanism in the flipped SO(10) models. The gauge group $SO(10)_F\times U(1)_{V'_F}$ includes $SU(2)_E$ gauge symmetry, that plays an important role in solving supersymmetric flavor problem by introducing non-abelian horizontal gauge symmetry and anomalous $U(1)_A$ gauge symmetry. The gauge group can be broken into the standard model gauge group by VEVs of only spinor fields, such models may be easier than $E_6$ models to be derived from the superstring theory.