I'm designing a SODA poll that would use facebook "like", google+ "+1", and/or reddit upvotes, along with automated delegated vote assignment, to give live-updated results. In thinking about this, I've realized that SODA can be nonmonotonic in the following (highly contrived) scenario:<div>
<br></div><div>(delegated preferences in parentheses)</div><div><br></div><div>35: A(>C)</div><div>30: B</div><div>25: C</div><div>10-n: X</div><div>n: Y(>B>A)</div><div><br></div><div>With n=4, A wins. With n=6, Y's votes are enough to make B win, so A approves C to prevent that from happening, and C wins; a worse result from the perspective of the Y voters.</div>
<div><br></div><div>The natural fix is to allow A to approve C with only some of their delegated votes. Then, when n=6, A can approve C with 12 votes. Now Y's votes cannot make B win, so Y approves A, and the nonmonotonicity is gone.</div>
<div><br></div><div>Of course, in order for this to work like that in a live poll, I have to make the logic for automatically updating assigned approvals much, much more complex. In fact, off the top of my head, I can't even prove that the general problem isn't NP-hard. But in real life, it's very unlikely that the scenario would be even this complex, so I'm not too worried about that.</div>
<div><br></div><div>Jameson</div>