| n0 < # x, n0 ≤ #(x to n0), ∀ m, x. m ≤ n0 ∧ n0 ≤ # x ∧ m ≤ # x → x to n0 to m = x to m ⊦ x to n0 to n0 = x to n0, x = [] |
n0 < # x, ∀ m, x. m ≤ n0 ∧ n0 ≤ # x ∧ m ≤ # x → x to n0 to m = x to m ⊦ x to n0 to n0 = x to n0, x = []
Used simplifier rules: length-to: ¬ # x < n ⊦ #(x to n) = n;% ⊦ m ≤ m; (s)% ⊦ m < n → ¬ n < m; (s)