ON SYMMETRIES OF KDV-LIKE EVOLUTION EQUATIONS

The x-dependence of the symmetries of (l+l)-dimensional, scalar, translationally invariant evolution equations is described. A sufficient condition of (quasi)polynomiality in time t of the symmetries of evolution equations with constant separant is found. A general form of time dependence of the symmetries of KdV-like noniinearizable evolution equations is presented.