| m0 < n, ∀ n, x. m0 ≤ n → lastn(m0, lastn(n, x)) = lastn(m0, x) ⊦ n = 0, lastn(m0, lastn(n - 1, x.butlast)) = lastn(m0, x.butlast) |
n = m + 1, m0 < n, ∀ n, x. m0 ≤ n → lastn(m0, lastn(n, x)) = lastn(m0, x) ⊦ n = 0, lastn(m0, lastn(m, x.butlast)) = lastn(m0, x.butlast)
Used simplifier rules: n ≠ 0 ⊦ m = n - 1 ↔ n = m + 1; (elim) Used terms: n, m