Section circle_continuity.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma bet_cases : forall B C D1 D2,
C<>B ->
Definitions.BetS D1 B D2 ->
Definitions.BetS D1 C D2 ->
Definitions.BetS D1 B C \/ Definitions.BetS C B D2.