I'll get to the rest later, but:

robert bristow-johnson wrote:

To take an 1D example, the society would be like this:

    ###        ###
   #####      #####
######################
0-----A----------B-----1

whereas a "centrist" society is like this:

          ##
        ######
  ##################
0-----A----------B-----1


[snip]

If all voters agree about an ideal position (like in the centrist society above), then there will always be a Condorcet winner. If not, there may be cycles.

boy, i'd like that explained quantitatively. i am not sure what is meant by "an ideal position". might you mean that all voters agree about one of two ideal positions (literally poles, making for a polarized electorate: "yer either fer W or you be agin' it")? if all voters agree about a single ideal position, doesn't that make for a trivial election? like, here in North Korea, we're all for the Dear Leader.

Okay. What this means is that if the distribution of voters makes up a function that decays from a central point (like a Gaussian), and this function has only a single peak (at the central point), and the issue space is one-dimensional, then there will always be a CW, no matter where the central point resides with respect to the candidates.

That does not mean that everybody is for Dear Leader. Consider a shifted example of the "centrist" society above:

           ##
         ######
   ##################
 0-------A------------B-1

Now, there will be some people who prefer B to A, but A is still going to win. The median voter is also closer to A than to B.

It's possible to generalize this to something that Warren calls the "DDH-median" for multidimensional issue space. See http://rangevoting.org/BlackSingle.html for a mathematical treatment of that.

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