Integrability and diffeomorphisms on target space.
Integrable three-dimensional coupled nonlinear dynamical systems related to centrally extended operator Lie algebras and their Lax type three-linearization
The Hamiltonian representation for a hierarchy of Lax type equations on a dual space to the Lie algebra of integro-differential operators with matrix coefficients, extended by evolutions for eigenfunctions and adjoint eigenfunctions of the corresponding spectral problems, is obtained via some special Bäcklund transformation. The connection of this hierarchy with integrable by Lax two-dimensional Davey-Stewartson type systems is studied.
Intertwining symmetry algebras of quantum superintegrable systems.
Invariant differential operators and Frobenius decomposition of a -variety. (Invariante Differentialoperatoren und die Frobenius-Zerlegung einer -Varietät.)