Indecomposable Fusion Products

Abstract

We analyse the fusion products of certain representations of the Virasoro algebra for c=-2 and c=-7 which are not completely reducible. We introduce a new algorithm which allows us to study the fusion product level by level, and we use this algorithm to analyse the indecomposable components of these fusion products. They form novel representations of the Virasoro algebra which we describe in detail. We also show that a suitably extended set of representations closes under fusion, and indicate how our results generalise to all (1,q) models.