Section par_trans_NID.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

(* Specifications: *)
Lemma par_dec_NID : decidability_of_parallelism <-> decidability_of_not_intersection.
Lemma par_trans__par_dec :
postulate_of_transitivity_of_parallelism ->
decidability_of_parallelism.
Lemma col_int : forall A B C,
Col A B C <-> ~ (~ Bet A B C /\ ~ Bet B C A /\ ~ Bet C A B).