Applying the Factorization Technique for Simplification
of Expressions Involving Differential Operator Inverses

Serguei P. Tsarev

Department of Mathematics
Krasnoyarsk State Pedagogical University
Lebedevoi, 89
660049, Krasnoyarsk, Russia
e-mail: tsarev@edk.krasnoyarsk.su

Using the formal theory of linear ordinary differential operators we develop
simplification and normalization techniques for manipulation of expressions
involving inverses of linear ordinary differential operators alongside with the
usual D=d/dx.  Applications to investigation of symmetries of nonlinear PDE are
discussed.