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