Intrinsic Stratifications of Analytic Varieties
  By attaching a Lie algebra of germs of analytic vector fields to every point of a (real or complex) analytic variety V we construct the Nagano foliation of the variety. We prove that the Nagano foliation of V is a stratification. The treatment of the subject is totally coordinate free but relies on the Oka-Cartan-Serre theory of coherent analytic sheaves. 
Fran\c{c}ois Treves
math.DG math.AP math.CV