The fusion rules for the Temperley-Lieb algebra and its dilute generalization

The Temperley-Lieb (TL) family of algebras is well known for its role in building integrable lattice models. Even though a proof is still missing, it is agreed that these models should go to conformal field theories in the thermodynamic limit and that the limiting vector space should carry a representation of the Virasoro algebra. The fusion rules are a notable feature of the Virasoro algebra. One would hope that there is an analogous construction for the TL family. Such a construction was proposed by Read and Saleur (2007 Nucl. Phys. B 777 316) and partially computed by Gainutdinov and Vasseur (2013 Nucl. Phys. B 868 223-70) using the bimodule structure over the TL algebras and the quantum group Uq (sl2). We use their definition for the dilute Temperley-Lieb (dTL) family, a generalization of the original TL family. We develop a new way of computing fusion by using induction and show its power by obtaining fusion rules for both dTL and TL. We recover those computed by Gainutdivov and Vasseur and new ones that were beyond their scope. In particular, we identify a set of irreducible TL-or dTL-representations whose behavior under fusion is that of some irreducibles of the minimal models of conformal field theory.