E7 type modular invariant Wess-Zumino theory and Gepner's string compactification

Gepner's model has realized string propagation on Calabi-Yau type manifolds in terms of conformal field theories. We study the correlation functions in E7 type modular-invariant Wess-Zumino-Witten theory which is relevant to a three-generation model. Our procedure is applicable to general off-diagonal modular-invariant theories. We determine the Yukawa couplings of the model and discuss their geometrical and phenomenological implications. We also clarify Verlinde's fusion rule in E7 modular-invariant theory. (orig.)