- λG,L,T1. â\9dªG,Lâ\9d« ⊢ T1 ![h,a] →
- â\88\80n1,T. â\9dªG,Lâ\9d« â\8a¢ T1 â\9e¡[h,n1] T â\86\92 T1 â\89\9b T →
- â\88\80n2,T2. â\9dªG,Lâ\9d« ⊢ T ➡[h,n2] T2 →
- â\88\83â\88\83T0. â\9dªG,Lâ\9d« â\8a¢ T1 â\9e¡[h,n2] T0 & â\9dªG,Lâ\9d« â\8a¢ T0 â\9e¡[h,n1] T2 & T0 â\89\9b T2.
+ λG,L,T1. â\9d¨G,Lâ\9d© ⊢ T1 ![h,a] →
+ â\88\80n1,T. â\9d¨G,Lâ\9d© â\8a¢ T1 â\9e¡[h,n1] T â\86\92 T1 â\89\85 T →
+ â\88\80n2,T2. â\9d¨G,Lâ\9d© ⊢ T ➡[h,n2] T2 →
+ â\88\83â\88\83T0. â\9d¨G,Lâ\9d© â\8a¢ T1 â\9e¡[h,n2] T0 & â\9d¨G,Lâ\9d© â\8a¢ T0 â\9e¡[h,n1] T2 & T0 â\89\85 T2.