<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<div class="moz-cite-prefix"><br>
BTV "known on this list for some time now as a superior option to
STV." Other systems, including BTV are not so regarded by
organisations, like the PRSA and Electoral Reform Society for well
over a century. Not to mention Fair Votes USA.<br>
<br>
Richard Lung.<br>
<br>
<br>
On 04/02/2018 19:18, Jameson Quinn wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAO82iZxCmA3FwOvzGWp=0RMV+dqyZkcXySoqqfr1wzT6KrSW6A@mail.gmail.com">
<div dir="ltr">Yes, I believe that many of these references refer
to what is essentially BTV, which has been known on this list
for some time now as a superior option to STV. I'm happy that
it's now in the literature, and don't really care about
naming/precedence.
<div><br>
</div>
<div>It's my experience that many prop-rep voting methods can be
expressed in terms of an STV backend. PLACE, Dual Member
Proportional, many MMP variants, etc. can all be seen as just
adding options (such as overlapping seats for MMP and DMP,
biproportionality for DMP and PLACE, and partial delegation
for PLACE) on top of STV. You could therefore create new
versions of all of the above by replacing STV with BTV. I
think this would be a small step up — but not worth the
additional difficulty of explanation, in a world that's more
used to STV.</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">2018-02-04 12:22 GMT-05:00 Kristofer
Munsterhjelm <span dir="ltr"><<a
href="mailto:km_elmet@t-online.de" target="_blank"
moz-do-not-send="true">km_elmet@t-online.de</a>></span>:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex"><span
class="">On 01/29/2018 02:43 PM, Arthur Wist wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
Hello,<br>
<br>
Sorry in advanced for the huge load of information all
at once, but I think you'll highly likely find the
following quite interesting:<br>
<br>
On how people misunderstood the Duggan-Schwartz theorem:<br>
<a href="https://arxiv.org/abs/1611.07105"
rel="noreferrer" target="_blank"
moz-do-not-send="true">https://arxiv.org/abs/1611.071<wbr>05</a>
- Two statements of the Duggan-Schwartz theorem<br>
<a href="https://arxiv.org/abs/1611.07102"
rel="noreferrer" target="_blank"
moz-do-not-send="true">https://arxiv.org/abs/1611.071<wbr>02</a>
- Manipulability of consular election rules<br>
<br>
EVERYTHING here:<br>
<a
href="https://scholar.google.com/citations?user=ssb0yjUAAAAJ&sortby=pubdate"
rel="noreferrer" target="_blank"
moz-do-not-send="true">https://scholar.google.com/cit<wbr>ations?user=ssb0yjUAAAAJ&sortb<wbr>y=pubdate</a><br>
<br>
Some key highlights from that last link above:<br>
<br>
<a href="https://arxiv.org/abs/1708.07580"
rel="noreferrer" target="_blank"
moz-do-not-send="true">https://arxiv.org/abs/1708.075<wbr>80</a>
- Achieving Proportional Representation via Voting [ On
which a blog post exists: <a
href="https://medium.com/@haris.aziz/achieving-proportional-representation-2d741871e78"
rel="noreferrer" target="_blank"
moz-do-not-send="true">https://medium.com/@haris.aziz<wbr>/achieving-proportional-repres<wbr>entation-2d741871e78</a>.
Better than STV and STV derivatives in all criteria? You
decide! ]<br>
</blockquote>
<br>
</span>
>From a cursory look at the latter, that looks like
Bucklin with a STV-style elect-and-reweight system. I wrote
some posts about a vote-management resistant version of
Bucklin at <a
href="http://lists.electorama.com/pipermail/election-methods-electorama.com/2016-December/001234.html"
rel="noreferrer" target="_blank" moz-do-not-send="true">http://lists.electorama.com/pi<wbr>permail/election-methods-elect<wbr>orama.com/2016-December/001234<wbr>.html</a>
and <a
href="http://lists.electorama.com/pipermail/election-methods-electorama.com/2017-September/001584.html"
rel="noreferrer" target="_blank" moz-do-not-send="true">http://lists.electorama.com/pi<wbr>permail/election-methods-elect<wbr>orama.com/2017-September/00158<wbr>4.html</a>,
and found out that the simplest way of breaking a tie when
more than one candidate exceeds a Droop quota is
nonmonotonic.<br>
<br>
The simplest tiebreak is that when there are multiple
candidates with more than a quota's worth of votes (up to
the rank you're considering), you elect the one with the
most votes. This can be nonmonotone in th following way:<br>
<br>
Suppose in the base scenario, A wins by tiebreak, and B has
one vote less at the rank q, so A is elected instead of B.
In a later round, say, q+1, E wins. Then suppose a few
voters who used to rank A>E decides to push E higher.<br>
<br>
Then B wins at rank q. If now most of the B voters vote E at
rank q+1, it may happen that the deweighting done to these
voters (since they got what they wanted with B being elected
instead of A) could keep the method from electing E.<br>
<br>
E.g. A could be a left-wing candidate, B be a right-wing
candidate, and E a center-right candidate. In the base
scenario, A wins and then the B voters get compensated by
having the center-right candidate win. But when someone
raises E, the method can't detect the left wing support and
so the right-wing candidate wins instead. Afterwards, the
right-wing has drawn weight away from E (due to E not being
a perfect centrist, but instead being center-right), and so
E doesn't win.<br>
<br>
Achieving monotonicity in multiwinner rules is rather hard;
it's not obvious how a method could get around the scenario
above without considering later ranks.<br>
<br>
I'm not sure if rank-maximality solves the problem above. If
it doesn't, then the above is an example of CM failure but
not RRCM failure.<br>
<br>
See also <a
href="http://lists.electorama.com/pipermail/election-methods-electorama.com/2012-January/094876.html"
rel="noreferrer" target="_blank" moz-do-not-send="true">http://lists.electorama.com/pi<wbr>permail/election-methods-elect<wbr>orama.com/2012-January/094876.<wbr>html</a>
and <a
href="http://lists.electorama.com/pipermail/election-methods-electorama.com/2012-February/095188.html"
rel="noreferrer" target="_blank" moz-do-not-send="true">http://lists.electorama.com/pi<wbr>permail/election-methods-elect<wbr>orama.com/2012-February/095188<wbr>.html</a>
for another Bucklin PR method that seemed to be monotone.<br>
<br>
It's also unknown whether Schulze STV is monotone, though it
seems to do much better than IRV-type STV in this respect.
And I'd add that there's yet another (very strong) type of
monotonicity not mentioned in the paper as far as I could
see. Call it "all-winners monotonicity" - raising a winner
on some ballot should not replace any of the candidates on
the elected council with anyone ranked lower on that ballot.<br>
<br>
(There's a result by Woodall that you can't have all of
LNHelp, LNHarm, mutual majority and monotonicity. Perhaps,
due to the difficulty of stopping the monotonicity failure
scenario above, the equivalent for multiwinner would turn
out to be "you can't have either LNHelp or LNHarm, and both
Droop proportionality and monotonicity"...)
<div class="HOEnZb">
<div class="h5"><br>
----<br>
Election-Methods mailing list - see <a
href="http://electorama.com/em" rel="noreferrer"
target="_blank" moz-do-not-send="true">http://electorama.com/em</a>
for list info<br>
</div>
</div>
</blockquote>
</div>
<br>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">----
Election-Methods mailing list - see <a class="moz-txt-link-freetext" href="http://electorama.com/em">http://electorama.com/em</a> for list info
</pre>
</blockquote>
<p><br>
</p>
<pre class="moz-signature" cols="72">--
Richard Lung.
<a class="moz-txt-link-freetext" href="http://www.voting.ukscientists.com">http://www.voting.ukscientists.com</a>
Democracy Science series 3 free e-books in pdf:
<a class="moz-txt-link-freetext" href="https://plus.google.com/106191200795605365085">https://plus.google.com/106191200795605365085</a>
E-books in epub format:
<a class="moz-txt-link-freetext" href="https://www.smashwords.com/profile/view/democracyscience">https://www.smashwords.com/profile/view/democracyscience</a>
</pre>
<div id="DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2"><br />
<table style="border-top: 1px solid #D3D4DE;">
<tr>
<td style="width: 55px; padding-top: 13px;"><a href="https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient" target="_blank"><img src="https://ipmcdn.avast.com/images/icons/icon-envelope-tick-round-orange-animated-no-repeat-v1.gif" alt="" width="46" height="29" style="width: 46px; height: 29px;" /></a></td>
<td style="width: 470px; padding-top: 12px; color: #41424e; font-size: 13px; font-family: Arial, Helvetica, sans-serif; line-height: 18px;">Virus-free. <a href="https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient" target="_blank" style="color: #4453ea;">www.avast.com</a>
</td>
</tr>
</table><a href="#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2" width="1" height="1"> </a></div></body>
</html>