Descending Solid Coalitions: Difference between revisions

imported>Kevin Lamoreau
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imported>Kevin Lamoreau
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Notice that more than half of the votes held Memphis to be the worst alternative, yet the Memphis supporters' votes were still useful in securing their second choice, Nashville. If the Memphis voters had not listed any preferences after Memphis, the winner would have been Chattanooga.
 
Since DSC satisfies [[Later-no-harm criterion|Later-no-harm]], it's not possible for a voter to get a better result by withholding lower preferences. ItSince isDSC possiblefails the [[Later-no-help criterion]], however, it is possible in some cases for a voter to get a better result for a candidate already ranked by ranking additional candidates below that candidate, or by changing the ranking of candidates ranked below that candidate such that at least one candidate is ranked above another candidate instead of being ranked the same as or below that candidate. The corrolary to this statement is that it is possible in some cases for a voter to get a worse result for a candidate by withholding preferences for candidates ranked below that candidate, or by changing the ranking of candidates ranked below that candidate such that at least one candidate is ranked the same as or below another candidate instead of being ranked above that candidate. If the Nashville voters had not listed any preferences after either Nashville or Chattanooga, or had ranked Memphis the same as or above either Knoxville or Chattanooga or both, the winner would have been Memphis, as the number of candidates strictly committed to the set {N,C,K} would have been only 32, which is less than the number of candidates strictly committed to at least the sets {M} and {M,N}. Regardless of the order in which those two sets (along with the set {M,N,C} if Nashville's voters had still all ranked Chattanooga ahead of Knoxville) were considered, Memphis would have been the only candidate remaining after those two or three sets were considered and so would have been the winner.
 
[[Category:Single-winner voting systems]]