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

Lemma mid_plgs :
forall A B C D M,
~ Col A B C ->
Midpoint M A C -> Midpoint M B D ->
Parallelogram_strict A B C D.