Hint Immediate col_trivial_1 col_trivial_2 col_trivial_3: col.
Section T4_4.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma col_cong_3_cong_3_eq : forall A B C A' B' C1 C2,
A <>B -> Col A B C -> Cong_3 A B C A' B' C1 -> Cong_3 A B C A' B' C2 -> C1 = C2.