proposition: Lemma free_monoidfun_homot_extend {X Y : hSet} (f : X → Y) : free_monoidfun f ~ free_monoid_extend (free_monoid_unit ∘ f).
proof: Proof. exact (foldr1_concatenate f). Defined.
imports: UniMath.MoreFoundations.Subtypes UniMath.MoreFoundations.Sets UniMath.Algebra.Monoids UniMath.Algebra.Groups UniMath.Algebra.IteratedBinaryOperations UniMath.Combinatorics.Lists