[EM] What's known about SCRRIRVE? Raynaud.

[MIKE OSSIPOFF]

James--

You wrote:

Burying is still a significant problem in SCRRIRVE, but as for whether it
is more or less of a problem than in WV, I'll have to go into that later,
since I don't have much time just at the moment.

I reply:

What we have so far is an example in which offensive order-reversal doesn't 
work in SCRRIRVE. We don't have a demonstration that anything less than 
defensive favorite-burial can be depended on to prevent offensive 
order-reversal from succeeding. We don't have a demonstration that SCRRIRVE 
is truncation-resistant in any sense, much less that it matches wv in that 
regard.

In other words, we have pretty much no demonstrations of any advantages of 
SCRRIRVE.

You continued:

I note in passing that
SCRRIRVE seems to have some things in common with Raynaud (eliminate the
candidate who has the strongest beat against them and recalculate, until
there is an unbeaten candidate), since they are both elimination-based
Condorcet methods. Perhaps someone else (Markus?) can tell us why Raynaud
isn't discussed more often. I imagine that there is a good reason for it,
since Raynaud is just about as obvious as WV minimax / sequential
dropping, and thus must have been discussed at some point.

I reply:

Suppose B,  the middle CW, has fewest 1st place votes. Say the A voters 
order-reverse. Say the CW's voters defensively truncate:

40: ACB
25: C
35: CBA

B has the biggest pairwise defeat, 75. B is eliminated, and with just A & C 
remaining, A is now the unbeaten candidate and wins.

With wv, the A voters' offensive order-reversal backfires, due to the 
defensive truncation, and is therefore well-deterred.

With margins? Don't expect any good properties that way, since margins' 
subtractions erase majority information.

Mike Ossipoff

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