On a Metric Kemeny’s Median
The Kemeny’s median represents the coordinated ranking as the opinion of an expert group. Such an opinion is the least different from others in the group and is free of some contradictions (Arrow’s paradox) in the well-known majority rule problem. The new problem of building the Kemeny’s median with metric characteristics is being developed in this paper. It is assumed, rankings represented by pairwise distances between them are immersed as a set in some Euclidean space. In this case, we can define the mean element as the center of this set. Such central element is a ranking as well and must be similar to the Kemeny’s median. The mathematically correct Kemeny’s median needs to be seen as the center in its distances to other elements. A new procedure is developed to build the modified loss matrix and find the metric Kemeny’s median.
KeywordsKemeny’s median Rank aggregation Majority rule Arrow’s paradox Pairwise comparison Metrics
This research was partially supported by the Russian Foundation for Basic Research (RFBR) grants 15-05-02228, 15-07-08967, 17-07-00319, 17-07-00436.
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