2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/55032Graphs which generalize the simple or affine Dynkin diagrams are introduced. Each diagram defines a bilinear form on a root system and thus a reflection group. We present some properties of these groups and of their natural "Coxeter element". The folding of these graphs and groups is also discussed, using the theory of C-algebras. (Proceedings of the Taniguchi Symposium {Topological Field Theory, Primitive Forms and Related Topics}, Kyoto Dec 1996)plain tex, 7 figuresHigh Energy Physics - Theorytext