Three counter-examples on semi-graphoids

Raymond Hemmecke, Jason Morton, Anne Shiu, Bernd Sturmfels, Oliver Wienand

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Semi-graphoids are combinatorial structures that arise in statistical learning theory. They are equivalent to convex rank tests and to polyhedral fans that coarsen the reflection arrangement of the symmetric group Sn. In this paper we resolve two problems on semigraphoids posed in Studeny's book (2005), and we answer a related question of Postnikov, Reiner and Williams on generalized permutohedra. We also study the semigroup and the toric ideal associated with semi-graphoids.

Original languageEnglish (US)
Pages (from-to)239-257
Number of pages19
JournalCombinatorics Probability and Computing
Issue number2
StatePublished - Mar 2008

All Science Journal Classification (ASJC) codes

  • Theoretical Computer Science
  • Statistics and Probability
  • Computational Theory and Mathematics
  • Applied Mathematics


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