Similar to the three-dimensional Cartesian coordinate system (x,y,z), #Nostr can be thought of a non-Euclidean cyberspace coordinate system of (n,e) where n is a 32 byte #npub, and e is a 32 byte hash of an event.

With (n,e) you can reference and attribute anything in cyberspace. That’s all you need for a standardized coordinate system. With #Nostr, you get some additional nice things like Schnorr signatures and and event kinds, but these are conventions, not core to the standardized coordinate system.

Thus, in the physical realm, you have (x,y,z) and in the digital realm (n,e).

Time (t) can be added, but that’s a function of the observer.