  We present a method for the implicitization problem that goes back to the
work of Sederberg and Chen. The formalism we use, with approximation complexes
as a key ingredient, is due to Jean-Pierre Jouanolou and was explained in
details in this context in his joint work with Laurent Buse. Most of this note
is dedicated to presenting the method, the geometric ideas behind it and the
tools from commutative algebra that are needed. In the last section, we give
the most advanced results we know related to this approach.
