  These are lecture notes of a course on symmetry group analysis of
differential equations, based mainly on P. J. Olver's book 'Applications of Lie
Groups to Differential Equations'. The course starts out with an introduction
to the theory of local transformation groups, based on Sussman's theory on the
integrability of distributions of non-constant rank. The exposition is
self-contained, pre-supposing only basic knowledge in differential geometry and
Lie groups.
