proposition: Lemma suppa_sym : forall A B C D E F, SuppA A B C D E F -> SuppA D E F A B C.
proof: Proof. unfold SuppA. intros; spliter. ex_and H0 A'. apply conga_distinct in H1; spliter. split; auto. destruct (segment_construction D E D E) as [D' []]. exists D'. split; auto. assert_diffs. apply conga_right_comm, l11_13 with A' D; Between. apply conga_sym, conga_right_comm, H1. Qed.
imports: GeoCoq.Tarski_dev.Ch10_line_reflexivity_2