| n < # kar, m < # ar, ∀ m0, m1. m0 < # kar ∧ ¬ n < m0 ∧ m1 < # kar ∧ ¬ n < m1 ∧ m0 ≠ m1 → kar[n, key-index(key, m)][m0].idx ≠ kar[n, key-index(key, m)][m1].idx, ∀ m. m < n → kar[m].idx < # ar ∧ ar[kar[m].idx].idx = m ⊦ valid-idx(kar[n, key-index(key, m)], ar[m, ar[m].idx:= n], n + 1) |
⊦ valid-idx(kar, ar, n) ↔ n ≤ # kar ∧ (∀ m. m < n → kar[m].idx < # ar ∧ ar[kar[m].idx].idx = m)
m < # ar, n < # kar, ∀ m. m < n → kar[m].idx < # ar ∧ ar[kar[m].idx].idx = m, ∀ m0, m1. m0 < # kar ∧ ¬ n < m0 ∧ m1 < # kar ∧ ¬ n < m1 ∧ m0 ≠ m1 → kar[n, key-index(key, m)][m0].idx ≠ kar[n, key-index(key, m)][m1].idx ⊦ n + 1 ≤ # kar[n, key-index(key, m)] ∧ (∀ m0. m0 < n + 1 → kar[n, key-index(key, m)][m0].idx < # ar[m, ar[m].idx:= n] ∧ ar[m, ar[m].idx:= n][kar[n, key-index(key, m)][m0].idx].idx = m0)
Used terms: n + 1, ar[m, ar[m].idx:= n], kar[n, key-index(key, m)]