intros; apply (@Build_Isomorphic _ _ C a c (#i1 >>> #i2) (#i2⁻¹ >>> #i1⁻¹));
setoid_rewrite juggle3;
[ setoid_rewrite (iso_comp1 i2) | setoid_rewrite (iso_comp2 i1) ];
intros; apply (@Build_Isomorphic _ _ C a c (#i1 >>> #i2) (#i2⁻¹ >>> #i1⁻¹));
setoid_rewrite juggle3;
[ setoid_rewrite (iso_comp1 i2) | setoid_rewrite (iso_comp2 i1) ];