fact: Definition make_subrig {X : rig} : ∏ (t : hsubtype X), (λ A : hsubtype X, issubrig A) t → ∑ A : hsubtype X, issubrig A := tpair (λ A : hsubtype X, issubrig A).
imports: UniMath.Algebra.Groups UniMath.MoreFoundations.Sets UniMath.MoreFoundations.Orders UniMath.Algebra.Monoids