proposition: Lemma mon_lunitor_triangle_transposed (x : V) : mon_lunitor (monoidal_unit V ⊗_{V} x) = mon_rassociator I_{V} I_{V} x · mon_lunitor I_{V} ⊗^{V}_{r} x.
proof: Proof. rewrite <- (when_bifunctor_becomes_rightwhiskering V). etrans. 2: { apply maponpaths, mon_lunitor_triangle. } rewrite assoc. refine (! id_left _ @ _). apply maponpaths_2. apply pathsinv0. apply monoidal_associatorisolaw. Qed.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Limits.BinProducts UniMath.CategoryTheory.PrecategoryBinProduct UniMath.CategoryTheory.Monoidal.WhiskeredBifunctors UniMath.CategoryTheory.Monoidal.Categories UniMath.CategoryTheory.Monoidal.Structure.Symmetric