Hash-table principles (4)
The hash function must be consistent:
k1 = k2 implies hash(k1) = hash(k2).
In general, the hash function is many-to-one.
Therefore different keys may share the same home bucket:
k1 ? k2 but hash(k1) = hash(k2).
This is called a collision.
Always prefer a hash function that makes collisions relatively infrequent.