[EM] summary answers

[Jobst Heitzig]

Some correction.

I wrote:
> In the sincere situation
> x A>>D>B>C
> y B>>D>C>A
> z C>>D>A>B
> the winner should be one of A,B,C, with probability x/n, y/n, z/n, respectively, since D is not approved by anyone. 
> 
> DFC (Democratic Fair Choice) gives this result!

The last is wrong, of course. DFC is not so extreme but still gives D
some probability, depending on the relative sizes of x,y,z:

Without loss of generality, assume that x is larger than y,z. Then
either y>z and DFC will elect A with prob. x/n and D with prob. (y+z)/n.
Or y<z and DFC will elect A with prob. x/n, C with prob. z/n, and D with
prob. y/n.

Sorry for messing up the example,
Jobst