| ∀ a. (x0 -1l a) -l a = x0 -l a ⊦ ((a0 ' + x0) -1l a) -l a = (a0 ' + x0) -l a, a = a0 |
∀ a. (x0 -1l a) -l a = x0 -l a ⊦ (x0 -1l a) -l a = x0 -l a, a = a0
Used simplifier rules: del1-n: ⊦ a ≠ b → (b ' + x) -1l a = b ' + (x -1l a);%del-n: ⊦ a ≠ b → (b ' + x) -l a = b ' + (x -l a);% ⊦ x + y = x + z ↔ y = z; (s)%a: ⊦ (x + y) + z = x + y + z; from specification list