| a = a0, ∀ y, a. (x0 + y) -l a = (x0 -l a) + (y -l a) ⊦ ((a0 ' + x0) + y) -l a = ((a0 ' + x0) -l a) + (y -l a) |
∀ y, a. (x0 + y) -l a = (x0 -l a) + (y -l a) ⊦ (x0 + y) -l a0 = (x0 -l a0) + (y -l a0)
Used simplifier rules: del-y: ⊦ (a ' + x) -l a = x -l a;%a: ⊦ (x + y) + z = x + y + z; from specification list