Difference between revisions of "River"

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River is a cloneproof monotonic [[Condorcet_method#Different_ambiguity_resolution_methods|Condorcet ambiguity resolution method]] with similarities to both [[Ranked Pairs]] and [[Schulze method|Cloneproof Schwartz Sequential Dropping]], but when cycles exist, can in rare cases find a different winner than either of the other two methods.
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River is a cloneproof monotonic [[Condorcet_method#Different_ambiguity_resolution_methods|Condorcet ambiguity resolution method]] with similarities to both [[Ranked Pairs]] and [[Schulze method|Schulze]], but when cycles exist, can in rare cases find a different winner than either of the other two methods.
  
 
Quick summary of method, which is identical to Ranked Pairs except where emphasized:
 
Quick summary of method, which is identical to Ranked Pairs except where emphasized:

Revision as of 18:25, 3 December 2005

River is a cloneproof monotonic Condorcet ambiguity resolution method with similarities to both Ranked Pairs and Schulze, but when cycles exist, can in rare cases find a different winner than either of the other two methods.

Quick summary of method, which is identical to Ranked Pairs except where emphasized:

  • Rank defeats in descending order of winning vote strength.
  • Starting with the strongest defeat, affirm defeats unless a cycle is created or a candidate is defeated twice.

The result is that only sufficient defeat information to determine the winner is included.

Because not all defeats are processed, the social ordering is not linear -- in general it is a tree (or river) diagram, with the victor at the base of the river.

It was first proposed by Jobst Heitzig on the Election-methods mailing list: