On 07/13/2012 05:30 PM, Fred Gohlke wrote:
Good Morning, Dave
re: "Clones are a problem for Plurality, and primaries were
invented to dispose of clones within a party"
I'm not sure what clones are, but imagine they are multiple candidates
who seek the same office.
Strictly speaking, clones are candidates that are so alike each other
that every voter ranks them next to each other (but not necessarily in
the same order). A method passes the independence of clones criterion if
adding or removing clones never alters who wins - unless the winner was
cloned (in which case one of the clones may win) or the winner was one
of the clones removed (in which case a remaining clone may win).
Plurality fails the independence of clones criterion because splitting a
candidate into clones can make them lose (vote-splitting). Borda fails
it because splitting a candidate into clones can make one of the clones
win (teaming). Copeland fails because adding or removing clones of some
candidate A can make the win go from B to C (crowding).
More generally speaking, a clone could be considered a candidate that's
very close to an already existing candidate and whose presence changes
who wins.
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