Abstract
Dr. A. Matsuo has been working on various mathematical structures related to two-dimensional conformal field theory. He is famous for his study on the Knizhnik-Zamolodchkov equation and its analogues. He is recently interested in searching for examples of vertex algebras having interesting symmetries. Dr. K. Nagatomo is working on the theory of vertex oeprator algebras and related topics. His interests include applications of the representation theory of infinite dimensional algebras to completely integrable systems. He dedicates this paper to Dr. Matsuo's daughter who was born a few days ago.