| ⊦ m < # x → sublist(m, 1, x) = x[m] ' |
Used simplifier rules: sublist-def: ⊦ sublist(m, n, x) = firstn(n, restn(m, x));%first-num: n ≠ 0 ⊦ firstn((* n), x) = x.first ' + firstn(n -1, x.rest);%firstN-zero: ⊦ firstn(0, x) = [];%restn-first-get: ⊦ n < # x → restn(n, x).first = x[n];%c-04: ⊦ a ' = b ' ↔ a = b; from specification list%a: ⊦ (x + y) + z = x + y + z; from specification list%app: ⊦ x + [] = x; from specification list