, Volume 84, Issue 2, pp 431–439 | Cite as

Probing the h-core: an investigation of the tail–core ratio for rank distributions

  • Fred Y. Ye
  • Ronald Rousseau


The set of citations received by a set of publications consists of citations received by articles in the h-core and citations received by articles in the h-tail. Denoting the cardinalities of these fours sets as C, P, C H and C T we introduce the tail-core ratio (C T/C H) and show that in practical cases this ratio tends to increase. Introducing further the k-index, defined as k = (C/P)/(C T/C H), we show that this index decreases in most practical cases. A power law model is in accordance with these practical observations.


h-Index h-Core h-Tail Tail–core ratio v-Index k-Index 



Fred Y. Ye’s work is supported by a grant from the National Natural Science Foundation of China (NSFC Grant No. 70773101), while Ronald Rousseau’s work is supported by the National Natural Science Foundation of China Grant No. 70673019. The authors thank graduate student Jianhui Tang for assistance in data collection and Leo Egghe for checking the power law calculations.


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Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2009

Authors and Affiliations

  1. 1.Department of Information Resources ManagementZhejiang UniversityHangzhouChina
  2. 2.Institute of Scientific and Technical Information of ChinaBeijingChina
  3. 3.Department of Industrial Sciences and TechnologyKHBO (Association K.U.Leuven)OostendeBelgium
  4. 4.Department of MathematicsK.U.LeuvenHeverlee, LeuvenBelgium

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