Interesting connection, but Datomic's EAV (Entity-Attribute-Value) model solves a different problem than Graham's universal relation. In the "Universal relation problem," we're fighting with consistency across arbitrary join paths. This problem is more about the NP-completeness of maintaining consistency across all possible join paths

Datomic's approach is more like a temporal log of facts, it's not trying to maintain universal join consistency across all possible paths. The EAV model lets you treat everything as "facts over time" (Datomic's strength yes) instead trying to make every possible join path consistent