(* no other convenient place to expose these facts *)

(* Specifications: *)
Axiom simplify_sound : forall l c s,
listd clause_denote inter TT l s -> clause_denote c s ->
clause_denote (simplify l c) s.
Axiom simplify_atoms_sound : forall l sigma s,
listd clause_denote inter TT l s -> space_denote sigma s ->
space_denote (simplify_atoms l sigma) s.