Require Export GeoCoq.Tarski_dev.Ch14_prod.
Section Order.
Context `{T2D:Tarski_2D}.
Context `{TE:@Tarski_euclidean Tn TnEQD}.

Lemma ltP_sum_pos : forall O E E' A B C , Ps O E B -> Sum O E E' A B C -> LtP O E E' A C.