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arXiv · 1001.0920

Online Correlation Clustering

Claire Mathieu·Ocan Sankur·Warren Schudy
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Abstract

We study the online clustering problem where data items arrive in an online fashion. The algorithm maintains a clustering of data items into similarity classes. Upon arrival of v, the relation between v and previously arrived items is revealed, so that for each u we are told whether v is similar to u. The algorithm can create a new cluster for v and merge existing clusters. When the objective is to minimize disagreements between the clustering and the input, we prove that a natural greedy algorithm is O(n)-competitive, and this is optimal. When the objective is to maximize agreements between the clustering and the input, we prove that the greedy algorithm is .5-competitive; that no online algorithm can be better than .834-competitive; we prove that it is possible to get better than 1/2, by exhibiting a randomized algorithm with competitive ratio .5+c for a small positive fixed constant c.

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Claire Mathieu, Ocan Sankur, Warren Schudy. 2010-02-03. Online Correlation Clustering. https://arxiv.org/abs/1001.0920

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