Intertwining relations of non-stationary Schr\"odinger operators
  General first- and higher-order intertwining relations between non-stationary one-dimensional Schr\"odinger operators are introduced. For the first-order case it is shown that the intertwining relations imply some hidden symmetry which in turn results in a $R$-separation of variables. The Fokker-Planck and diffusion equation are briefly considered. Second-order intertwining operators are also discussed within a general approach. However, due to its complicated structure only particular solutions are given in some detail. 
F. Cannata (1), M. Ioffe (2), G. Junker (3) and D. Nishnianidze (2)   ((1) Dipartimento di Fisica and INFN, Bologna, Ttaly, ...