F_ind2@{i j} (P : F -> F -> Type@{i}) {sP : forall x y, IsHProp (P x y)} (dclass : forall x y : Frac R, P (' x) (' y)) : forall x y, P x y. Proof. apply (@F_ind (fun x => forall y, _)). - intros;apply istrunc_forall@{UR i j}. - intros x. apply (F_ind _);intros y. apply dclass. Qed.
Require Import HoTT.HIT.quotient. Require Import Import Frac.