The L(sl_2) symmetry of the Bazhanov-Stroganov model associated with the superintegrable chiral Potts model

The loop algebra $L({\mathfrak{s}\mathfrak{l}}_2)$ symmetry is found in a sector of the nilpotent Bazhanov-Stroganov model. The Drinfeld polynomial of a $L({\mathfrak{s}\mathfrak{l}}_2)$-degenerate eigenspace of the model is equivalent to the polynomial which characterizes a subspace with the Ising-like spectrum of the superintegrable chiral Potts model.