-theorem nth_repl: â\88\80C1,C2. C1 â\89\88 C2 â\86\92 â\88\80i,l1,l2. l1 â\89\88 l2 →
- nth i ? l1 C1 â\89\88 nth i ? l2 C2.
+theorem nth_repl: â\88\80C1,C2. C1 â\89\85 C2 â\86\92 â\88\80i,l1,l2. l1 â\89\85 l2 →
+ nth i ? l1 C1 â\89\85 nth i ? l2 C2.