fact: Definition isinvringmultgt (X : ring) (R : hrel X) : UU := dirprod (∏ a b, R (a * b) 0 -> R a 0 -> R b 0) (∏ a b, R (a * b) 0 -> R b 0 -> R a 0).
imports: UniMath.Algebra.Groups UniMath.MoreFoundations.Sets UniMath.MoreFoundations.Orders UniMath.Algebra.Monoids