| z + x + a ' + y = x ⊦ |
z + x + a ' + y = x ⊦ #(z + x + a ' + y) = # x
Used simplifier rules: ⊦ #(x + y) = # x + # y; (s)% ⊦ # a ' = 0 +1; (s)%a: ⊦ (x + y) + z = x + y + z; from specification list% ⊦ m = m + n ↔ n = 0; (s)% ⊦ m + 1 ≠ 0; (s)%a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic%c: ⊦ m + n = n + m; from specification nat-basic Used formulas: #(z + x + a ' + y) = # x