Section Tarski_to_intuitionistic_Tarski.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.
Definition BetH A B C : Prop := Bet A B C /\ A <> B /\ B <> C.

Lemma bet_stability : forall A B C, ~ ~ BetH A B C -> BetH A B C.