Yes, while I'm aware we could write those 2 relationships, from a COGS perspective it is "quite a lot of tuples to add to the database" at our scale. That's right, we are creating permissions that would depend on that reverse permission, and actually quite a niche one that does further make it difficult to justify duplicating millions of tuples. The left pointing arrow seems interesting. At least for us, it would be necessary that the semantics are "all objects of a given type that point to me via a specific relation in that type".