Definition issymmlogeqf {X : UU} {L R : hrel X} (lg : ∏ x1 x2, L x1 x2 <-> R x1 x2) (isl : issymm L) : issymm R. Proof. intros. intros x1 x2 r12. apply (pr1 (lg _ _) (isl _ _ (pr2 (lg _ _) r12))). Defined.
Require Import UniMath.Foundations.UnivalenceAxiom.