Section T11_1.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma l11_4_1 : forall A B C D E F,
CongA A B C D E F -> A<>B /\ C<>B /\ D<>E /\ F<>E /\
(forall A' C' D' F', Out B A' A /\ Out B C' C /\ Out E D' D /\ Out E F' F /\
Cong B A' E D' /\ Cong B C' E F' -> Cong A' C' D' F').