Require Export GeoCoq.Elements.OriginalProofs.euclidean_defs.
Require Export GeoCoq.Elements.OriginalProofs.general_tactics.
Ltac remove_double_neg :=
repeat
match goal with
H: ~ ~ ?X |- _ => apply NNPP in H
end.
Section basic_lemmas.
Context `{Ax:euclidean_neutral}.

Lemma nCol_notCol :
forall A B C, ~ Col A B C -> nCol A B C.