(* Lemma test17 : forall A B C D E F G H I J K L : Point, S A B C + S B A C + S D E F + S E D F + S G H I + S I G H + S A J K + S K J A + S A B C + S B A C + S A B C + S B B C + S A B C + S B A C + S A B C + S B B C + S A B C + S B A C + S J K L + S K L J + S A B C + S B A C + S A B C + S B A C + S A B C + S B A C + S A B C + S B A C + S A B C + S B A C + S A B C + S B A C + S A B C + S B A C + S D E F + S E D F + S G H I + S I G H + S A J K + S K J A + S A B C + S B A C + S A B C + S B B C + S A B C + S B A C + S A B C + S B B C + S A B C + S B A C + S J K L + S K L J + S A B C + S B A C + S A B C + S B A C + S A B C + S B A C + S A B C + S B A C + S A B C + S B A C + S A B C + S B A C + S A B C + S B A C + S D E F + S E D F + S G H I + S I G H + S A J K + S K J A + S A B C + S B A C + S A B C + S B B C + S A B C + S B A C + S A B C + S B B C + S A B C + S B A C + S J K L + S K L J + S A B C + S B A C + S A B C + S B A C + S A B C + S B A C + S A B C + S B A C + S A B C + S B A C + S A B C + S B A C + S A B C + S B A C + S D E F + S E D F + S G H I + S I G H + S A J K + S K J A + S A B C + S B A C + S A B C + S B B C + S A B C + S B A C + S A B C + S B B C + S A B C + S B A C + S J K L + S K L J + S A B C + S B A C + S A B C + S B A C + S A B C + S B A C + S A B C + S B A C + S A B C + S B A C + S A B C + S B A C =0 -> 0=0. *)

Lemma test172 : forall A B C, S A B C <> 0 -> S C B A = 0 -> S B C A =0 -> 0=1.