- λR. â\88\80b,f,L1,K1. â¬\87*[b, f] L1 â\89¡ K1 →
- â\88\80K2,T. K1 ⪤*[R, T] K2 â\86\92 â\88\80U. â¬\86*[f] T â\89¡ U →
- â\88\83â\88\83L2. L1 ⪤*[R, U] L2 & â¬\87*[b, f] L2 â\89¡ K2 & L1 â\89\90[f] L2.
+ λR. â\88\80b,f,L1,K1. â¬\87*[b, f] L1 â\89\98 K1 →
+ â\88\80K2,T. K1 ⪤*[R, T] K2 â\86\92 â\88\80U. â¬\86*[f] T â\89\98 U →
+ â\88\83â\88\83L2. L1 ⪤*[R, U] L2 & â¬\87*[b, f] L2 â\89\98 K2 & L1 â\89¡[f] L2.