fact: Definition laxleftunitor {C : category} (tu : tensor_unit C) : UU := ∑ lu : leftunitor_data tu tu, leftunitor_nat lu.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Monoidal.WhiskeredBifunctors UniMath.CategoryTheory.Monoidal.Categories