I’m confused. Do you mean “worlds” as in “future trajectories of the world” or as in “subcommunities of AI researchers”? And what’s a concrete example of gains from trade between worlds?
Subcommunities of AI researchers. A simple concrete example of gains from trade is when everyone uses the same library or conceptual methodology, and someone finds a bug. The primary ones of interest are algorithmic gains; the new thing used to do better lipreading can also be used by other researchers to do better on other tasks (or to further enhance this approach and push it further for lipreading).