| a ∈ y, ∀ y. perm(x0, rmdup(rev(y))) ↔ perm(x0, rmdup(y)) ⊦ perm(x0, rmdup(rev(y) -l a)) ↔ perm(x0, rmdup(y -l a)) |
⊦ rev(x) -l a = rev(x -l a)
a ∈ y, ∀ y. perm(x0, rmdup(rev(y))) ↔ perm(x0, rmdup(y)) ⊦ perm(x0, rmdup(rev(y -l a))) ↔ perm(x0, rmdup(y -l a))
Used terms: a, y