Require Export GeoCoq.Tarski_dev.Ch09_plane.
Require Export GeoCoq.Tarski_dev.Tactics.CoincR_for_cop.
Ltac CopR :=
let tpoint := constr:(Tpoint) in
let col := constr:(Col) in
let cop := constr:(Coplanar) in
assert_ncols; Cop_refl tpoint col cop.
Section T10.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma ex_sym : forall A B X, exists Y, (Perp A B X Y \/ X = Y) /\
(exists M, Col A B M /\ Midpoint M X Y).