Here, only the owner object is able to forge and share aliases for its owned objects. Subjects which have acquired such aliases are not able to copy them, that is, the aliases are confined and locally unique. The owner, so, is a kind of a "alias factory", it can own how much aliases it desire, and delegate how much it wish, but of course it must have at least one reference to copy that owned object.
Such discipline is strongly related to the Non-Delegatable Authority pattern in the Object-Capability Model[1].
- [1] Non-Delegatable Authorities in Capability Systems — by Toby Murray and Duncan Grove