A Lie Algebraic Approach
                           Jan Sanders

                    Wiskunde en Informatica,
                  Vrije Universiteit Amsterdam
                      e-mail: jansa@can.nl

    Two  examples are given of algorithms based on the  imbedding 
in  a Lie algebra of a given linear operator.  The first  is  the 
computation   of  non-semisimple  normal  forms  of  systems   at 
equilibrium,  using sl(2) and the second the computation of  e.g. 
conservation  laws  of PDEs using the  3  dimensional  Heisenberg 
algebra  as an extension of the total  differentiation  operator. 
Both algorithms have been implemented in Maple programs producing
Form code.