fact: Definition presented_gr_intro {X : hSet} {R : hrel (free_gr X)} : X → presented_gr X R := presented_gr_pr R ∘ free_gr_unit.
imports: UniMath.MoreFoundations.Subtypes UniMath.MoreFoundations.Sets UniMath.Algebra.Monoids UniMath.Algebra.Groups UniMath.Algebra.IteratedBinaryOperations UniMath.Combinatorics.Lists