Conservation Laws and τ-Symmetry Algebra of the Gerdjikov–Ivanov Soliton Hierarchy.

Two hierarchies of isospectral and nonisospectral Gerdjikov–Ivanov equations are constructed. Conservation laws of the isospectral soliton hierarchy are explicitly derived from a specific Riccati equation that a ratio of two eigenfunctions satisfies. The corresponding K-symmetries and τ -symmetries formulated from the isospectral and nonisospectral hierarchies constitute an infinite-dimensional τ -symmetry algebra for the isospectral hierarchy. [ABSTRACT FROM AUTHOR]