Don't despair. Datalog is alive and well. Yes, it does compose beautifully. However, with composition solved, you'll discover that a naive implementation of relational algebra will suffer from spurious cross products.
This is pretty interesting stuff, thanks for sharing! Does temporal information get any special treatment in the economic graph at the moment? Are temporal queries of any interest?
I ask because I work on Crux [0] which at its core is a point-in-time bitemporal Datalog engine, and I see a lot of similarities (schemaless core, Worst-Case Optimal Join etc.)
