| m ≤ # x0, ∀ m, a. m < # x0 → #oc(a, x0[m, a]) = #oc(a, x0) + 1 ∨ x0[m] = a ∨ x0 = [] ⊦ #oc(a0, (a0 ' + x0)[m, a0]) = 2 + #oc(a0, x0), (a0 ' + x0)[m] = a0 |
⊦ x ≠ [] ∧ n ≠ 0 → x[n] = x.tail[n - 1]
m ≤ # x0, ∀ m, a. m < # x0 → #oc(a, x0[m, a]) = #oc(a, x0) + 1 ∨ x0[m] = a ∨ x0 = [] ⊦ #oc(a0, (a0 ' + x0)[m, a0]) = 2 + #oc(a0, x0), a0 ' + x0 = [], (a0 ' + x0).tail[m - 1] = a0, m = 0
Used simplifier rules: ocappend: ⊦ #oc(a, x + y) = #oc(a, x) + #oc(a, y);%one: ⊦ #oc(a, a ') = 1;% ⊦ a ' + x ≠ []; (s)%a: ⊦ (x + y) + z = x + y + z; from specification list% ⊦ (b ' + x)[0, a] = a + x; (s)% ⊦ a + x = a ' + x; (s)% ⊦ m + n = m + n0 ↔ n = n0; (s)%a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic%c: ⊦ m + n = n + m; from specification nat-basic% ⊦ (a ' + x)[0] = a; (s) Used terms: m, a0 ' + x0