  Lie symmetry analysis provides a general theoretical framework for
investigating ordinary and partial differential equations. The theory is
completely algorithmic even if it usually involves lengthy computations. For
this reason, many computer algebra packages have been developed along the years
to automate the computation. In this paper, we describe the program ReLie,
written in the Computer Algebra System Reduce, which since 2008 is an open
source program (http://www.reduce-algebra.com) and is available for all
platforms. \relie is able to perform almost automatically the needed
computations for Lie symmetry analysis of differential equations. Its source
code is freely available at the url http://mat521.unime.it/oliveri. The use of
the program is illustrated by means of some simple examples; nevertheless, it
is to be underlined that it provides effective also for more complex
computations where one has to deal with very large expressions.
