ON A GENERALIZED BOOTSTRAP PRINCIPLE

The S-matrices for non-simply-laced affine Toda field theories are con sidered in the context of a generalised bootstrap principle. The S-mat rices, and in particular their poles, depend on a parameter whose rang e lies between the Coxeter numbers of dual pairs of the corresponding non-simply-laced algebras. It is proposed that only odd order poles in the physical strip with positive coefficients throughout this range s hould participate in the bootstrap. All other singularities have an ex planation in principle in terms of a generalised Coleman-Thun mechanis m. Besides the S-matrices introduced by Delius, Grisaru and Zanon, the missing case (f4(1), e6(2)) is also considered and provides many inte resting examples of pole generation.