<br><br><div class="gmail_quote">2012/2/1 Kevin Venzke <span dir="ltr"><<a href="mailto:stepjak@yahoo.fr">stepjak@yahoo.fr</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div><div style="font-size:12pt;font-family:times new roman,new york,times,serif"><div><span>Hi Jameson,</span></div>
<div><span></span> </div>
<div><span>I expect that unpredictability (whatever there may be) of candidates' decisions can only hurt criteria compliance.</span></div>
<div><span>At least with cri<var></var>teria that are generally defined on votes, because with such criteria you usually have to assume</span></div>
<div><span>the worst about any other influences incorporated into the method.</span></div></div></div></blockquote><div><br></div><div>This is true. For most of the criteria, I was implicitly talking about a version of SODA where all candidates use optimum strategy according to their predeclared preferences. This is well-defined and unique, but is not necessarily polytime-calculable. Still, even without being able to calculate results, you can prove criteria compliances for this version by contradiction. </div>
<div><br></div><div>For a polytime-calculable version which satisfies most of the same criteria, assume that each candidate, when it is their turn to assign delegated votes, looks at the two "distinct frontrunners"; that is:</div>
<div>Candidate X, their most-preferred member of the current Smith set</div><div>and candidate Y, the candidate, of those whom they prefer differently from X, who does best pairwise (again, using current assignments and unassigned preferences) against X</div>
<div>They approve as many candidates as possible without approving both X and Y.</div><div><br></div><div>This version does not satisfy participation (though again, it's damn close) or IIA, and I'm not 100% sure about its cloneproofness (though I think it is). Otherwise, it satisfies the criteria I said.</div>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div style="font-size:12pt;font-family:times new roman,new york,times,serif">
<div><span></span> </div>
<div><span>So I wonder, can you suggest a deterministic version of SODA, where the "negotiations" of SODA are instead</span></div>
<div><span>calculated directly from the pre-announced preferences of the candidates? And if so, does it satisfy the same</span></div>
<div><span>criteria in your view</span><span>?</span></div>
<div><span></span> </div>
<div><span>I can say I would be skeptical of how a criterion is being applied, or how clearly it is being defined, if the </span></div>
<div><span>satisfaction of it *depends* on </span><span>the </span><span>fact that candidates have post-voting decisions to make.</span></div></div></div></blockquote><div><br></div><div>Are you still suspicious of participation and [delegated] IIA, given that satisfying them depends on assuming optimal strategy?</div>
<div><br></div><div>Jameson </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div style="font-size:12pt;font-family:times new roman,new york,times,serif">
<div><span></span> </div>
<div><span>Kevin</span></div>
<div><span></span> </div>
<div><span></span> </div>
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</div><b><span style="FONT-WEIGHT:bold">De :</span></b> Jameson Quinn <<a href="mailto:jameson.quinn@gmail.com" target="_blank">jameson.quinn@gmail.com</a>><br><b><span style="FONT-WEIGHT:bold">À :</span></b> EM <<a href="mailto:election-methods@lists.electorama.com" target="_blank">election-methods@lists.electorama.com</a>> <br>
<b><span style="FONT-WEIGHT:bold">Envoyé le :</span></b> Mardi 31 janvier 2012 20h50<br><b><span style="FONT-WEIGHT:bold">Objet :</span></b> [EM] SODA criteria<br></font></div><div><div class="h5"><br>
<div>SODA passes:
<div><br></div>
<div>Majority</div>
<div>MMC (as voted)</div>
<div>Condorcet (as voted, and in a strong Nash equilibrium as honest)</div>
<div>Condorcet loser (ditto)</div>
<div>Monotone</div>
<div>Participation (with the fix that delegation can be any fraction)</div>
<div>IIA (delegated version - that is, if a new candidate is added, the winner is either the same, or someone higher on the new candidate's delegation order.)</div>
<div>Cloneproof</div>
<div>Polytime (there is no guarantee that optimal delegated assignment strategy is polytime calculable, but it will be in any real case, and anyway, candidates can just choose some near-optimal strategy.)</div>
<div>Resolvable</div>
<div>Summable</div>
<div>Allows equal rankings</div>
<div>FBC</div>
<div><br></div>
<div>So, of the criteria in the <a href="http://en.wikipedia.org/wiki/Voting_system#Compliance_of_selected_systems_.28table.29" rel="nofollow" target="_blank">wikipedia voting systems table</a>, the only ones it out-and-out fails are:</div>
<div>Consistency (though it comes damn close)</div>
<div>Later-no-harm and later-no-help (though it does satisfy LNHarm for the one (two????) candidate(s?) with the most voted approvals, and for other candidates, adding later preferences is probably strategically forced; so I'd say it fulfills the spirit of both of these. Similarly, it satisfies LNHelp for the last-to-delegate candidate, and nearly so for other late-delegating candidates, and the point of LNHelp is to prevent a weak candidate from winning through clever bottom filling, so again it satisfies the spirit.)</div>
<div>Allows later preferences (though delegation substitutes for this affordance in some cases.)</div>
<div><br></div>
<div>If we could just get some wikipedia-notable mention of SODA, we could put it in the table, and I think it would graphically stand out as the most criteria-compliant method there.</div>
<div><br></div>
<div>I'm working on an academic article on SODA, which would not be focused on these criteria or even on SODA, but would quickly state the above. But if anyone can make an article happen in a wikipedia "reliable source", that would be great.</div>
<div><br></div>
<div>Jameson</div>
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