A counterpart of the WKI soliton hierarchy associated with so(3,R)
  A counterpart of the Wadati-Konno-Ichikawa (WKI) soliton hierarchy, associated with so(3,R), is presented through the zero curvature formulation. Its spectral matrix is defined by the same linear combination of basis vectors as the WKI one, and its Hamiltonian structures yielding Liouville integrability are furnished by the trace identity. 
Wen-Xiu Ma, Solomon Manukure and Hong-Chan Zheng
nlin.SI math-ph math.MP