[EM] Simple example of FPTP being no monotonic

Stéphane Rouillon stephane.rouillon at sympatico.ca
Fri Nov 7 11:50:20 PST 2008


Let us try a language you understand:

- more voters prefer B to C

- a fraction of those voters will vote for A because they even prefer A to 
other candidates

- thus C can get elected because of vote-splitting between A and B

Even if more voters prefer B to C, the result is that C wins over B. This is 
clearly non-monotonic.
This is a typical vote-splitting case using FPTP.

Now do you understand in what reality we live today?
I do. This is why I consider alternatives.

Yours, Stéph.

>From: "Kathy Dopp" <kathy.dopp at gmail.com>
>Reply-To: kathy.dopp at gmail.com
>To: "Stéphane Rouillon" <stephane.rouillon at sympatico.ca>
>CC: election-methods at lists.electorama.com
>Subject: Re: [EM] New MN court affidavits by those 
>defendingnon-Monotonicvoting methods
>Date: Fri, 7 Nov 2008 11:35:02 -0700
>
>On Fri, Nov 7, 2008 at 7:45 AM, Stéphane Rouillon
>
> > Exactly, no electoral system can garantee coherence between the order of
> > preferences of a voter
> > and the impact the participation of that voter has on the result.
>
>Yea Right! The vote counting method that is employed cannot guarantee
>the coherence of "the impact the participation of that voter has on
>the result".
>
>What alternate reality are we living in today?
>
>Kathy
>----
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