In this monograph the authors redevelop the theory systematically using
two different approaches. A general mechanism for the deformation of
structures on manifolds was developed by Donald Spencer ten years ago. A
new version of that theory, based on the differential calculus in the
analytic spaces of Grothendieck, was recently given by B. Malgrange. The
first approach adopts Malgrange's idea in defining jet sheaves and
linear operators, although the brackets and the non-linear theory arc
treated in an essentially different manner. The second approach is based
on the theory of derivations, and its relationship to the first is
clearly explained. The introduction describes examples of Lie equations
and known integrability theorems, and gives applications of the theory
to be developed in the following chapters and in the subsequent volume.