| ⊦ n < # kar ∧ m < # ar ∧ valid-idx(kar, ar, n) ∧ no-dups-idx(kar[n, key-index(key, m)], n + 1) → (¬ valid-idx(kar[n, key-index(key, m)], ar[m, ar[m].idx:= n], n + 1) ↔ false) |
n < # kar, m < # ar, no-dups-idx(kar[n, key-index(key, m)], n + 1), valid-idx(kar, ar, n) ⊦ ¬ valid-idx(kar[n, key-index(key, m)], ar[m, ar[m].idx:= n], n + 1) ↔ false