First I have a typo correction in my example (inspired by Bart) showing that ordinal ballot methods satisfying neutrality and the Condorcet Criterion are manipulable, even when non-deterministic.

I gave the last faction as z C>B>A, when I meant z C>A>B. The entire corrected tableaux is

  x  A>C>B
  y  B>C>A
  z  C>A>B .

From: Forest Simmons <[EMAIL PROTECTED]>
Subject: [EM] Re: lotteries

<snip>


However, even though it is non-deterministic, and highly manipulation
resistant, it is not totally manipulation free:

(following Bart's critique on non-determinism...)

Suppose that there are three factions with sincere preferences

  x A>C>B
  y B>C>A
  z C>B>A ,


Now for James' message

Date: Wed, 05 Jan 2005 21:17:42 -0500
From: "James Green-Armytage" <[EMAIL PROTECTED]>
Subject: Re: [EM] There is always a Condorcet Winner! (among all
        lotteries of    candidates :
To: "Jobst Heitzig" <[EMAIL PROTECTED]>,
        election-methods-electorama.com@electorama.com

<James wrote>

Dear Jobst,

        Yes, it does sound like an intriguing idea, although non-deterministic
methods have never been an area of expertise for me.
        In its present state, the proposal is still a little bit too abstract 
for
me to grasp; as usual, it's easier for me to understand a tally method
once I am given an example of it in practice. So, could you please find
the Condorcet lottery for the following group of preferences, and show me
how you did it?

35: A>B>C>D
25: B>C>A>D
30: C>A>B>D
10: D>C>A>B

thanks!
James Green-Armytage

<Forest replies>

There are only three uncovered candidates here A, B, and C, and they form a cycle, so they also form the set W, and the winning "lottery" is the distribution p(A)=p(B)=p(C)=1/3 .


It's easy to get this once you realize that Lottery is just Spruced Up Random Candidate.



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