Re: April 17th Draft of the Voting GR
>> On Fri, 18 Apr 2003 17:54:46 -0400,
>> Raul Miller <moth@magenta.com> said:
>> > I've also made explicit that only undropped defeats are used in
>> > determining the schwartz set.
> On Fri, Apr 18, 2003 at 04:05:06PM -0500, Manoj Srivastava wrote:
>> Whoa there. I think A transitively defeats option C if a defeats B
>> and B defeats C, whether or not the defeat is dropped.
> Why do you think that?
Because I think that defeats are a lower level construct than
the Schwartz set. A defeats B is well defined (whetrher or not we are
going to use the Schwartz set later on to determine a
winner). Similarly, A can transitively defeat B, using the common
definition of transitive, irrespective of the later actions. Note
that in case of circular ties, a may transitively defeat C, and C may
transitively defeat A.
This does not help us determine the winner, of course, so we
seek to break the tie, such that one of the above statements
is no longer true. In other words, A transitively beats C, but after
adjusting the schwartz set, C no longer transitively beats A
(considering only the undropped defeats).
In order to define this last condition, I am introducing the
concept of unconditional defeats, like shown below (I think we had
been straining the definition of a transitive defeat -- we were
certainly defining it so that it caused me some confusion).
Of course, now I see that transitive defeats are become
irrelevant, and this devolves down to what you had proposed, but I
still find this version less confusing.
Comments?
----------------------------------------------------------------------
Replace A.6 with:
A.6 Vote Counting
1. Each voter's ballot ranks the options being voted on. Not all
options need be ranked. Ranked options are considered
preferred to all unranked options. Voters may rank options
equally. Unranked options are considered to be ranked equally
with one another. Details of how ballots may be filled out
will be included in the Call For Votes.
2. If the ballot has a quorum requirement R any options other
than the default option which do not receive at least R votes
ranking that option above the default option are dropped from
consideration.
3. Any (non-default) option which does not defeat the default option
by its required majority ratio is dropped from consideration.
a. Given two options A and B, V(A,B) is the number of voters
who prefer option A over option B.
b. An option A defeats the default option D by a majority
ratio N, if V(A,D) is strictly greater than N * V(D,A).
c. If a supermajority of S:1 is required for A, its majority ratio
is S; otherwise, its majority ratio is 1.
4. From the list of undropped options, we generate a list of
pairwise defeats:
a. An option A defeats an option B, if V(A,B) is strictly greater
than V(B,A).
b. (A,B) is a defeat of option B if option A defeats option B.
c. An option A transitively defeats an option C if A
defeats C or if there is some other option B where A
defeats B AND B transitively defeats C.*2
5. We construct the Schwartz set from (a subset of) the list of
pairwise defeats.*1
- If (A,C) is an undropped defeat then option A
unconditionally defeats option C.
- If (A,B) is an undropped defeat, and option B
unconditionally defeats option C, then option A
unconditionally defeats option C.
- An option A is in the Schwartz set if for all options B,
considering only the undropped defeats, either A
unconditionally defeats B, or B does not unconditionally
defeat A.
If there are defeats between options in the Schwartz set, we
drop the weakest such defeats from the list of pairwise
defeats, and return to step 5.
a. A defeat (A,X) is weaker than a defeat (B,Y) if V(A,X)
is less than V(B,Y). Also, (A,X) is weaker than (B,Y)
if V(A,X) is equal to V(B,Y) and V(X,A) is greater than
V(Y,B).
b. A weakest defeat is a defeat that has no other defeat
weaker than it. There may be more than one such defeat.
6. If there are no defeats within the Schwartz set, then the winner
is chosen from the options in the Schwartz set. If there is
only one such option, it is the winner. If there are multiple
options, the elector with the casting vote chooses which of those
options wins.
*1 Please note that in case of circular ties, unconditional defeats
cannot be determined, and thus the tie must be broken in order to
determine the outcome.
*2 Please note that in the face of circular ties, A may transitively
defeat C, and, simultaneously, C may transitively defeat A.
----------------------------------------------------------------------
manoj
--
Check me if I'm wrong, Sandy, but if I kill all the golfers... they're
gonna lock me up and throw away the key!
Manoj Srivastava <srivasta@debian.org> <http://www.debian.org/%7Esrivasta/>
1024R/C7261095 print CB D9 F4 12 68 07 E4 05 CC 2D 27 12 1D F5 E8 6E
1024D/BF24424C print 4966 F272 D093 B493 410B 924B 21BA DABB BF24 424C
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