| x[m, x[n]][n] ≠ a ∧ a ≠ x[m] ∧ n < # x[m, x[n]], n < # x, m < # x ⊦ #oc(a, x[m, x[n]]) = #oc(a, x), x = [] |
m < # x, n < # x ⊦ #oc(a, x[m, x[n]]) = #oc(a, x), x = [], a = x[m], x[m, x[n]][n] = a
Used simplifier rules: put-length: ⊦ n < # x → # x[n, a] = # x; from specification list-del