(* Gabriel Braun April 2013 *)
Require Export GeoCoq.Tarski_dev.Ch13_1.
Section Length_1.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.
(** Pappus Desargues *)
(******************** length *********************)

Lemma lg_exists : forall A B, exists l, Q_Cong l /\ l A B.