$SU$(2) Hierarchies of Dilute Lattice Models

The fusion procedure of dilute $A_L$ models is constructed. It has been shown that the fusion rules have two types: $su(2)$ and $su(3)$. This paper is concerned with the $su(2)$ fusion rule mainly and the corresponding functional relations of commuting transfer matrices in the $su(2)$ fusion hierarchy are found. Specially, it has been found that the fusion hierarchy does not close. These two types of fusion generate different solvable models, but, they are not totally irrelevant. The $su(2)$ fusion of level $2$ is equivalent to the $su(3)$ fusion of level $(1,1)$. According to this relationship the Bethe ansatz of fused model of level $(1,1)$ in $su(3)$ hierarchy has been represented by that of level $2$ in $su(2)$ fusion hierarchy.