Definition free_abmonoid_hrel (X : hSet) : hrel (free_monoid X) := λ g h, ∃ x y, x * y = g × y * x = h.
Require Import UniMath.MoreFoundations.Subtypes. Require Import UniMath.MoreFoundations.Sets. Require Import UniMath.Algebra.Monoids. Require Import UniMath.Algebra.Groups. Require Import UniMath.Algebra.IteratedBinaryOperations. Require Import UniMath.Combinatorics.Lists.