| ⊦ n2 ≤ # x ∧ n + n1 ≤ n2 → sublist(n, n1, firstn(n2, x)) = sublist(n, n1, x) |
n2 ≤ # x, n + n1 ≤ n2, n + n1 ≤ # x ⊦ firstn(n1, restn(n, firstn(n2, x))) = firstn(n1, restn(n, x))
Used simplifier rules: sublist-def: ⊦ sublist(m, n, x) = firstn(n, restn(m, x));%let: ⊦ n ≤ n0 ∧ n0 ≤ n1 → n ≤ n1; (forward) from specification nat