-theorem ifr_unwind_bi (f) (p) (q) (t1) (t2):
- t1 Ο΅ π β t1β(pβπ¦) β§Έβ¬ π β
- t1 β‘π[p,q] t2 β βΌ[f]t1 β‘π[βp,βq] βΌ[f]t2.
+lemma ifr_unwind_bi (f) (p) (q) (t1) (t2):
+ t1 Ο΅ π β t1β(pβπ¦) β§Έβ¬ π β
+ t1 β‘π[p,q] t2 β βΌ[f]t1 β‘π[βp,βq] βΌ[f]t2.