Nonabelian duality and Higgs multiplets in supersymmetric grand unified theories

We consider strongly interacting supersymmetric gauge theories which dynamically break the GUT symmetry and produce light Higgs doublets naturally. Two models we proposed in previous articles are reanalyzed as two phases of one theory and are shown to have desired features. Furthermore, employing the nonabelian duality proposed recently by Seiberg, we study the dual theory of the above one and show that the low-energy physics of the original and dual models are the same as expected. We note that the Higgs multiplets in the original model are regarded as composite states of the elementary hyperquarks in its dual theory. Theories with other hypercolors and similar matter content are analyzed in the same way. (author)