This feels a bit like those relativity puzzles, for example the barn-pole paradox[1]. That is, delivered exactly-once seems to be a relative statement where on

This feels a bit like those relativity puzzles, for example the barn-pole paradox[1]. That is, delivered exactly-once seems to be a relative statement where one party can state they did deliver exactly-once while another party can disagree, and they're both correct relative to their local frames of reference. So, like how GR has no global conservation of energy, just local, could one say that distributed systems have no global conservation of messages, only local? Or am I just late night rambling again... [1]: https://en.wikipedia.org/wiki/Ladder_paradox https://en.wikipedia.org/wiki/Ladder_paradox