Definition prio1000 := Z2id 1000.Definition prio1001 := Z2id 1001.Definition clause_prio (cl : clause) : var :=
  match cl with
  | PureClause gamma delta prio _ => prio
  | PosSpaceClause _ _ _ => prio1000
  | NegSpaceClause gamma sigma delta => prio1001
  end%Z.Definition compare_clause' (cl1 cl2 : clause) : comparison :=
  match Ident.compare (clause_prio cl1) (clause_prio cl2) with
  | Eq => compare_clause cl1 cl2
  | c => c
  end.

Lemma clause_cspec': CompSpec' compare_clause'.