The Hamiltonian of the XXZ spin chain has the
sl2 loop algebra symmetry if the
q parameter is given by a root of unity,
q02N=1 , for an integer
N .We review an algorithm for determining the dimensions of the degenerate eigenspace generated by a given regular Bethe state in some sectors.The proof of the algorithm has been formulated in Ref.[3] as follows: We show in some sectors that regular Bethe ansatz eigenvectors are highest weight vectors and generate irreducible representations of the
sl2 loop algebra; We prove that every finite-dimensional highest weight representation of the
sl2 loop algebra is irreducible; We then derive the dimensions of the highest weight representation generated by a given regular Bethe state through the Drinfeld polynomial, which is expressed explicitly in terms of the Bethe roots.