[EM] Chris: various topics

[James Green-Armytage]

Hi Chris,
	Here is part 3 of my reply (miscellany). Deals with my different aspects
of my definitions page, and briefly with your "weak burial resistance"
criterion.

>I  don't know how anyone can think that "monotonicity"  (aka Woodall's
>Mono-raise) is worth mentioning (and/or worrying about) and at the same
>time wonder if
>these two "have any merit".  

	I only mention monotonicity on my criteria page because it is very
commonly considered by others, and because it implies vulnerability to
'paradoxical' strategies, which are mentioned elsewhere on my definition
page. So, don't blame me, I'm just following the crowd :-)

>I personally think that Mono-raise is nice, but too expensive because its
>incompatible with Weak Burial Resistance.
>Most of the criteria are "nice" and have at least some strong aesthetic
>appeal, and the reason why we don't have a method that meets them all is
>that some are
>incompatible with others. They all have some "price". Some we insist on
>at any price because they are about the fundamental aim of the method.
>One of  these 
>for me is (Mutual ) Majority. Others are always on our shopping list
>mainly because they are so "cheap", like Mono-add-plump and  Mono-append!.
>
	They may be cheap. I wouldn't know. If anything's incompatible with Smith
then I consider it to be too expensive.
	The thing is, nobody has convinced me that there is any particular reason
to care about mono-add-plump or mono-append. Maybe I should care about
them, but I know why I should, at least not as yet. So, even if they're
bargain-basement cheap, I don't see why I should buy them. 	
>
>
Chris:
>
>Probably WV should have a lower number  than Margins in the 
>>"compromising-reversal"  row,  because sometimes
>>in WV  compromising-compression can be an effective "defensive strategy" 
>>but to achieve the same effect those voters
>>in Margins  have to compromise-reverse.
>  
James:
>	That's interesting. Would you mind showing me an example? It sounds
>familiar, but I don't have anything like that on the surface (of my mind,
>or of my voting files).
Chris:
>This is classic  Ossipoff/Eppley/Tarr  stuff  from the Jurassic period
>of  WV versus Margins. This is from Steve Eppley's site:
>[ http://alumnus.caltech.edu/~seppley/Proof MAM satisfies Minimal Defense
>and Truncation Resistance.htm
>]http://alumnus.caltech.edu/~seppley/Proof%20MAM%20satisfies%20Minimal%20Defense%20and%20Truncation%20Resistance.htm

	Yeah, that's the kind of example I was looking for. Good point. I poked
the "margins" vulnerability to "compromising-reversal" up to 2, which
meant that I had to redo my table so that the scale is from 0 to 6 instead
of 0 to 5. I like the 0 to 6 scale better. Please have a look at the new
version when you get a chance. The ER-IRV version considered there is
fractional for now, but even so I might want to bring its paradoxical
score up to 2, eh?
>
>
James:
>
>I had a look
>at the weak burial resistance criterion, but I unfortunately found it
>somewhat confusing.
Chris:
>
>I'm sorry to hear that. Here it is:
>"If x is the CW (and wins), and on more than 1/3 of the ballots ranked
>above y and z; and afterwards on some of the ballots that rank y above x
>and x not below z, z's ranking relative to x is raised while keeping y
>ranked above them both, then if there is a new winner it cannot be y." 
>
	To me, this seems too specific to be called something as general as "weak
burial resistance". Plus, the wording is quite confusing. Maybe you could
write a simpler version, something like this: "If X is the CW and is
ranked first on more than 1/3 of the ballots, no faction can gain mutual
advantage by burying X."
	Or, a bit more general: "If C is the CW and is ranked above X and Y on
more than 1/3 of the ballots, the X>C faction cannot switch the winner
from C to X by burying C under Y." Not sure if these work, but they're
close.
	I still think that these criteria should be given a different name,
though. There are various ways to limit the burying strategy; protecting
candidates with >1/3 of the vote is only one of them. If you assume that
this is the most effective way to limit the burying strategy, then an IRV
completion method seems logical. However, I do not grant this assumption.
>
>
my best,
James