Section Circumcenter.
Context `{TE:Tarski_euclidean}.
Definition is_circumcenter G A B C := Cong A G B G /\ Cong B G C G /\ Coplanar G A B C.

Lemma is_circumcenter_perm_1 : forall A B C G,
is_circumcenter G A B C -> is_circumcenter G A C B.