(* Gabriel Braun November 2012 *)
Require Export GeoCoq.Tarski_dev.Ch12_parallel.
Section Quadrilateral.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma midpoint_preserves_bet :
forall A B C B' C',
Midpoint B' A B ->
Midpoint C' A C ->
(Bet A B C <-> Bet A B' C').