Require Export C15_Parallelogramm.
Section DISTANCE_PROPERTIES.

Lemma ChaslesLSltTrans : forall A B C D : Point,
A <> B ->
HalfLine A B C ->
HalfLine A C D ->
LSlt (Distance A B) (Distance A C) ->
LSlt (Distance A C) (Distance A D) ->
LSlt (Distance A B) (Distance A D).