proposition: Proposition internal_to_arr_id (x : V) : internal_to_arr (internal_id x) = identity x.
proof: Proof. unfold internal_to_arr. rewrite !assoc'. unfold internal_id. rewrite internal_beta. apply mon_linvunitor_lunitor. Qed.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.NaturalTransformations UniMath.CategoryTheory.FunctorCategory UniMath.CategoryTheory.Adjunctions.Core UniMath.CategoryTheory.Monoidal.WhiskeredBifunctors UniMath.CategoryTheory.Monoidal.Categories UniMath.CategoryTheory.Monoidal.Structure.Symmetric