fact: Definition presented_abgr_intro {X : hSet} {R : hrel (free_abgr X)} : X → presented_abgr X R := presented_abgr_pr R ∘ free_abgr_unit.
imports: UniMath.MoreFoundations.Subtypes UniMath.MoreFoundations.Sets UniMath.Algebra.Monoids UniMath.Algebra.Groups UniMath.Algebra.IteratedBinaryOperations UniMath.Combinatorics.Lists