- â\88\80K2,T. K1 ⦻**[R, T] K2 → ∀U. ⬆*[f] T ≡ U →
- â\88\83â\88\83L2. L1 ⦻**[R, U] L2 & â¬\87*[b, f] L2 â\89¡ K2 & L1 â\89¡[f] L2.
+ â\88\80K2,T. K1 ⪤**[R, T] K2 → ∀U. ⬆*[f] T ≡ U →
+ â\88\83â\88\83L2. L1 ⪤**[R, U] L2 & â¬\87*[b, f] L2 â\89¡ K2 & L1 â\89\90[f] L2.