Orbits and global unique continuation for systems of vector fields

SupposeM is a smooth manifold andV is a locally integrable vector subbundle of the complexified tangent bundle ofM. This paper explores the global unique continuation property of distribution solutions ofV, i.e., the distributionsu onM such thatLu = 0 wheneverL is a section ofV, and the closely related problem of the structure of the Sussmann orbits ofHV.