Section Cosinus2.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.
Global Instance lcos_morphism :
Proper (EqL ==> EqL ==> eq ==> iff) Lcos.

Lemma lcos2_uniqueness: forall l l1 l2 a b, Lcos2 l1 l a b -> Lcos2 l2 l a b -> EqL l1 l2.