[EM] New Condorcet/RP variant

Markus Schulze markus.schulze at alumni.tu-berlin.de
Thu Nov 11 08:46:46 PST 2004


> On the current wikipedia page for the Spoiler Effect,
> it says:
>    A voting system which satisfies the independence of
>    irrelevant alternatives criterion is immune to the
>    spoiler effect,
> Now, considering people use the term Spoiler Effect in
> the context of Independence of Clones Criterion , this
> statement would imply that satisfaction of IIR implies
> satisfaction of ICC.

There are two concepts of "spoilers": Arrow's concept of
"irrelevant alternatives" and Tideman's concept of "clones".

Neither does Arrow's concept of "irrelevant alternatives"
imply Tideman's concept of "clones" nor does Tideman's
concept of "clones" imply Arrow's concept of "irrelevant
alternatives". They are simply two completely different

So instead of asking which concept of "spoilers" is
correct, I suggest that the wikipedia page for "Spoiler
Effect" should start with the statement that there are
two completely different kinds of "spoilers" and then
this page should discuss these two kinds of "spoilers"
independently from each other.

Markus Schulze

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