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(* Formalization of the Chou, Gao and Zhang's decision procedure.          *)
(* Julien Narboux (Julien@narboux.fr)                                      *)
(* LIX/INRIA FUTURS 2004-2006                                              *)
(* University of Strasbourg 2008                                           *)
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(** nine point circle *)
(** another statement for nine point circle theorem *)

Lemma l6_44 : forall A B C G P Q I J,
is_midpoint J A C ->
is_midpoint I B C ->
inter_ll G J B I A ->
on_inter_line_parallel P G A B B C ->
on_inter_line_parallel Q G A C B C ->
G<>P ->
G<>Q ->
(2+2)*S4 P Q C B = (2+2+1)*S A Q P.