Pathspace Decompositions for the Virasoro Algebra and its Verma Modules

Starting from a detailed analysis of the structure of pathspaces of the ${\cal A}$-fusion graphs and the corresponding irreducible Virasoro algebra quotients $V(c,h)$ for the ($2,q$ odd) models, we introduce the notion of an admissible pathspace representation. The pathspaces ${\cal P_A}$ over the ${\cal A}$-Graphs are isomorphic to the pathspaces over Coxeter $A$-graphs that appear in FB models. We give explicit construction algorithms for admissible representations. From the finitedimensional results of these algorithms we derive a decomposition of $V(c,h)$ into its positive and negative definite subspaces w.r.t. the Shapovalov form and the corresponding signature characters. Finally, we treat the Virasoro operation on the lattice induced by admissible representations adopting a particle point of view. We use this analysis to decompose the Virasoro algebra generators themselves. This decomposition also takes the nonunitarity of the ($2,q$) models into account.