| n + m ≤ #(a + x0), ∀ n, m. n + m ≤ # x0 → x0 from m from n = x0 from m + n ⊦ a + x0 from m from n = a + x0 from m + n |
n + m ≤ 1 + # x0, ∀ n, m. n + m ≤ # x0 → x0 from m from n = x0 from m + n ⊦ a ' + x0 from m from n = a ' + x0 from m + n
Used simplifier rules: a: ⊦ (x + y) + z = x + y + z; from specification list% ⊦ # a ' = 0 +1; (s)% ⊦ #(x + y) = # x + # y; (s)% ⊦ a + x = a ' + x; (s)