This is not quite true. It's a mapping, but it's not a hash table because the mapping is bijective (while hash tables just project the keys into the table space

This is not quite true. It's a mapping, but it's not a hash table because the mapping is bijective (while hash tables just project the keys into the table space). So there is no possibility of collision, the number of keys is fixed, etc. It's just a table, like any other, and most of what is implied when talking about hash tables does not necessarily apply here.