Edit History last edit on [2022-07-30 Sat] I can refine this blog more by consolidating the current content to my notes on roam research. I don’t have time to do this at the time of writing. In theory, there is no need for “medium” of exchange. Any exchange can be anything as long as seller and buyer agree upon. Therefore, one can argue that there will always exist a sequence of exchanges of agreements that satisfy any pair of sellers and buyers.