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

Lemma mid_plg :
forall A B C D M,
(A <> C \/ B <> D ) ->
Midpoint M A C -> Midpoint M B D ->
Parallelogram A B C D.