(** LeA preserves SAMS. *)

Lemma sams_lea456_suma2__lea : forall A B C D E F G H I D' E' F' G' H' I',
LeA D E F D' E' F' -> SAMS A B C D' E' F' -> SumA A B C D E F G H I ->
SumA A B C D' E' F' G' H' I' -> LeA G H I G' H' I'.