Classification of Kac representations in the logarithmic minimal models image Original Research Article

For each pair of positive integers r, s, there is a so-called Kac representation image associated with a Yang–Baxter integrable boundary condition in the lattice approach to the logarithmic minimal model image. We propose a classification of these representations as finitely-generated submodules of Feigin–Fuchs modules, and present a conjecture for their fusion algebra which we call the Kac fusion algebra. The proposals are tested using a combination of the lattice approach and applications of the Nahm–Gaberdiel–Kausch algorithm. We also discuss how the fusion algebra may be extended by inclusion of the modules contragredient to the Kac representations, and determine polynomial fusion rings isomorphic to the conjectured Kac fusion algebra and its contragredient extension.