Abstract
A new Kaup-Newell type soliton hierarchy is generated from an asymmetric matrix spectral problem associated with the three-dimensional special linear Lie algebra sl(2, R). Then based on semi-direct sums of matrix Lie algebras consisting of 3 x 3 block matrix Lie algebras, corresponding bi-integrable couplings of this hierarchy are constructed. Each equation in the resulting system has a bi-Hamiltonian structure furnished by the variational identity, which lead to Liouville integrability. (C) 2014 Elsevier B.V. All rights reserved.