proposition: Lemma nlta__lea : forall A B C D E F, ~ LtA A B C D E F -> A <> B -> B <> C -> D <> E -> E <> F -> LeA D E F A B C.
proof: Proof. intros A B C D E F HNlta. intros. elim(conga_dec D E F A B C). apply conga__lea. intro. elim(lea_total D E F A B C); auto. intro. exfalso. apply HNlta. split; auto. apply not_conga_sym; assumption. Qed.
imports: GeoCoq.Tarski_dev.Ch10_line_reflexivity_2