<div dir="ltr"><div dir="ltr"><div class="gmail_default" style="font-family:trebuchet ms,sans-serif;font-size:small"><br></div></div><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Jul 6, 2021 at 9:58 PM Susan Simmons <<a href="mailto:suzerainsimmons@outlook.com">suzerainsimmons@outlook.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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<div>It appears that this IRV Tweak satisfies independence from Smith dominated alternatives.(ISDA)</div></div></blockquote><div><br></div><div><span style="font-family:"trebuchet ms",sans-serif">I'm really impressed. The method I was discussing a few days ago was not ISDA, was not independent of clones, and your method is easier to implement. Even for a fairly complex election anyone can quickly compute the winner with pencil and paper.<span class="gmail_default" style="font-family:"trebuchet ms",sans-serif;font-size:small"> I have no idea how to prove that a voting method satisfies ISDA but I've thought carefully about the independence of clones and I'm pretty sure I can confirm that yours is indeed independent of clones.</span></span></div><div><span style="font-family:"trebuchet ms",sans-serif"><span class="gmail_default" style="font-family:"trebuchet ms",sans-serif;font-size:small"><br></span></span></div><div><span style="font-family:"trebuchet ms",sans-serif"><span class="gmail_default" style="font-family:"trebuchet ms",sans-serif;font-size:small">Your method naturally extends to one that produces a full ranking: The candidate that is removed first is the lowest rank, and so on. It seems to me like this ranking satisfies </span></span>local independence from irrelevant alternatives<span class="gmail_default" style="font-family:"trebuchet ms",sans-serif;font-size:small">. </span><span style="font-family:"trebuchet ms",sans-serif">If you remove the lowest<span class="gmail_default" style="font-family:"trebuchet ms",sans-serif;font-size:small"> or highest</span> ranked candidate, the order of the remaining candidates does not change.<span class="gmail_default" style="font-family:"trebuchet ms",sans-serif;font-size:small"> I'm not sure how to prove this because to me it looks self-evident, but it's weird because very few methods satisfy LIIA. The table on Wikipedia only lists Ranked Pairs and Kemeny-Young as satisfying LIIA.</span></span></div><div><br></div><div class="gmail_default" style="font-family:"trebuchet ms",sans-serif;font-size:small">I'm actually surprised that this isn't a well-known method already. You'd think someone would have thought of it before.</div><div class="gmail_default" style="font-family:"trebuchet ms",sans-serif;font-size:small"><br></div><div class="gmail_default" style="font-family:"trebuchet ms",sans-serif;font-size:small">Daniel.</div></div></div>