Definition pbuchf :
  forall PQ : list (poly A0 eqA ltM) * list (poly A0 eqA ltM),
  {R : list (poly A0 eqA ltM) | OBuch (fst PQ) (snd PQ) R}.Definition strip :
  forall P : list (poly A0 eqA ltM) -> Prop, sig P -> list (poly A0 eqA ltM).

Theorem pbuchf_Stable : forall P R : list (poly A0 eqA ltM), R = strip _ (pbuchf (P, genOCPf P)) -> stable P R.