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A link between (i) the Peccei-Quinn mechanism, (ii) the canonical fermion mass matrix, and (iii) minimal grand unification is established. The effects of a global versus a local horizontal U(1) symmetry are analyzed. It is pointed out that the weak CP nonconservation in such a model has to be accounted for by Higgs exchanges. A possible bridge to composite models is noted.
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Davidson et al. (1982) studied this question.
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