Assumptions: You know why you want to use program
LIE that finds the Lie group, or rather the Lie algebra, of
differential equations, ordinary or partial, single or simultaneous,
and you can use the output of this program to find special similarity
solutions, conserved quantities, reductions of order etc. For
example, you have seen the books "Applications of Lie Groups
to Differential Equations" by P. J. Olver ( and the worked examples
in Chapters 2 and 3 ) or "Symmetries and Differential Equations"
by G. W. Blumen and S. Kumei or the article "Symmetries of Differential
Equations: from Sophus Lie to Computer Algebra" by F. Schwarz,
SIAM Review, vol 30, Sept 1988, pp450-481. Many of the examples
in the DAT files are from these sources. Source code is included.

There is now a companion program BIGLIE51 that
can handle problems that are too big for LIE.

(from the documentation)