How do special and general relativity differ in this model?

In the model, special relativity is what you get from the causal graph alone: causal invariance plus the freedom to slice events into different "moments of now" gives time dilation and a maximum signal speed in otherwise flat spacetime. General relativity is the claim you get when you add curvature — the hypergraph that is space can bend, and that bending is gravity — so that the relativity of time and the curving of space become inseparable. The first is argued to be derived in the model; the second, the route to full Einstein gravity, is claimed only in limited cases and remains incomplete.