| ⊦ zbrar[n] = mkzbranch(key, adr, r) ∧ sorted(zbrar, 0, nused) ∧ n < len ∧ len ≤ nused ∧ nused ≤ # zbrar → scan(key, zbrar, 0, len) = n |
zbrar[n] = mkzbranch(key, adr, r), n < len, sorted(zbrar, 0, nused), len ≤ nused, nused ≤ # zbrar ⊦ scan(key, zbrar, 0, len) = n