| n = n0 + # buf0, # buf0 ≤ n, n + m ≤ # buf0 + # buf1 ⊦ isempty(buf0 + buf1, n, m) ↔ isempty(buf1, n0, m) |
n0 + m ≤ # buf1 ⊦ isempty(buf0 + buf1, n0 + # buf0, m) ↔ isempty(buf1, n0, m)
Used simplifier rules: ⊦ m ≤ m + n; (s)%c: ⊦ m + n = n + m; from specification nat-basic%a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic% ⊦ m + n ≤ m + n0 ↔ n ≤ n0; (s)