摘要

In this paper, a subalgebra A(2) of the Lie algebra A(2) is constructed, which gives a corresponding loop algebra A(2) by properly choosing the gradation of the basis elements. It follows that an isospectral problem is established and a new Liouville integrable Hamiltonian hierarchy is obtained. By making use of a matrix transformation, a subalgebra A(2) of the Lie algebra A(1) is presented, which possesses the same communicative operations of basis elements as those in A(2). Again we expand the Lie algebra A(1) into a high-dimensional loop algebra G, and a type of expanding integrable system of the hierarchy obtained above is worked out. Furthermore, Hamiltonian structures of hierarchy are presented by use of the quadratic form identity.