[EM] Re: majority rule, mutinous pirates, and voter strategy

James Green-Armytage jarmyta at antioch-college.edu
Fri Mar 18 18:38:37 PST 2005


Hi Juho,
	Further replies follow on the topic of Smith methods vs.
minimax(margins)...
>
>Sorry about causing some gray hair to you. 

	Sorry about being peevish in my reply.

============
     track one
============
>
>one where we talk about dynamics of 
>sequential mutinies and how the voters may stop the process already 
>before the first mutiny when they see the votes and understand the 
>rules of the game, 
...
>I think your conclusions on the first track made all the sense, so 
>let's consider them agreed.

	Does this mean you agree that foresight of potential further mutinies is
likely to deter mutinies against Smith set candidates?
	Does it mean you acknowledge that this foresight will not necessarily
protect non-Smith candidates?
	Does it mean you agree that candidate Z (the non-Smith Condorcet loser)
is likely to be the most mutiny-vulnerable candidate in my RSTZ example? 
	Does it mean you are willing to abandon the claim that minimax(margins)
winners are less vulnerable to mutiny than Smith winners, when they differ?
>
>I identified also some possible additional scenarios:
>- An alternative model where the cost of mutiny is low and therefore 
>mutinies could continue forever (instead of stopping when pirates 
>understand that the cost of mutinies is too high). Accepting one of the 
>Smith candidates to take permanent lead may thus be more painful than 
>"sharing the leadership" by making continuous mutinies.

	In real life government/election scenarios, the cost of mutiny is always
high.

>- B and C could join forces and make just one revolution where A would 
>be changed to C (202 against 101) and stop there. 

	You suggest that the B>C>X>A and C>A>X>B pirates may join forces to
change A to C. In forming this coalition, the B>C>X>A pirates would
promise the C>A>X>B pirates that they would not mount a further mutiny
against C. But why should the C>A>X>B faction trust them on this, mutinous
pirates that they are? Once the first mutiny has occurred, the B>C>X>A
pirates could join forces with the disgruntled A>B>X>C faction, to get
their man B at the helm. 
	To be fair, I acknowledge that some mutinies might have more "sticking
power" than others. I suggest that this will depend on the strength of the
preferences involved, and so I suggest that cardinal pairwise may do
better in this sort of situation than any strictly ordinal method.

=============
       track 2
=============

>and another one where we try to do the decision just 
>once and then live with the result until the next election day (few 
>years ahead).
...
>Captain A would have more problems driving her policy through since C 
>could always make counter proposals that would be supported 202 against 
>101 and A would need better speaking skills than X (or a cannon).
>
	This doesn't make a whole lot of sense to me so far, perhaps because I
don't understand the scenario. To begin with, we're assuming that there is
an extremely strong sincere cycle in the initial vote. I doubt that this
will happen very often (probably never to the extent of your example), but
I can accept the premise for the sake of argument. But then, are we
assuming that there would be a comparably strong cycle in the sincere
preferences of the voters on most public issues? I think that this is much
less probable.
	Let's dump the pirate metaphor for track 2, and start talking about
actual government institutions. Is A the president now? What do you mean,
"problems driving her policy through"? Is the president supposed to write
legislation, and then rely on a popular ranked vote to have it passed? Who
says that the president has to win the vote on every issue? If A is
president, but the X faction wins the vote on several issues, that's fine
with me.

my best,
James Green-Armytage
http://fc.antioch.edu/~james_green-armytage/voting.htm



===========
      annex
===========

ANNEX 1: The pirate example.

101: a>b>x>c
101: b>c>x>a
101: c>a>x>b
100: x

ANNEX 2: The RSTZ example.

	Preferences:
35: R>S>T>Z
33: S>T>R>Z
32: T>R>S>Z
71: Z>R=S=T
	Pairwise comparisons:
R>S 67-33
S>T 68-32
T>R 65-35
R>Z 100-71
S>Z 100-71
T>Z 100-71







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