Polynomial Lax pairs for the chiral O(3)-field equations and the Landau-Lifshitz equation

Abstract

New Lax pairs for the chiral O(3)-field equations and for the Landau-Lifshitz equation have been found. In contrast to the already-known pairs, these pairs are polynomial in the spectral parameter lambda . We also find a new 4*4 Lax pair in the case of cnoidal waves for the generalized Landau-Lifshitz equation.