| n < # x ⊦ x = firstn(n, x) + restn(n, x), x = [] |
n0 +1 < # x, ∀ x. n0 < # x → x = firstn(n0, x) + restn(n0, x) ∨ x = [] ⊦ x = [], x = firstn(n0 +1, x) + restn(n0 +1, x)
Used simplifier rules: firstN-zero: ⊦ firstn(0, x) = [];%restN-zero: ⊦ restn(0, x) = x;%nat freely generated by 0, +1;;% ⊦ [] + x = x; (s)%a: ⊦ (x + y) + z = x + y + z; from specification list