(** Strongly sorted: elements of the list are pairwise ordered *)

(* Specifications: *)
Lemma StronglySorted_inv : forall a l, StronglySorted (a :: l) ->
StronglySorted l /\ Forall (R a) l.
Lemma StronglySorted_Sorted : forall l, StronglySorted l -> Sorted l.
Lemma Sorted_extends :
Transitive R -> forall a l, Sorted (a::l) -> Forall (R a) l.
Lemma Sorted_StronglySorted :
Transitive R -> forall l, Sorted l -> StronglySorted l.