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PC-Trees and Planar Graphs

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28<br />

Some coloring theorems of Kneser hypergraphs<br />

AUTHOR: Peng-An Chen 陳鵬安<br />

Department of Mathematics, National Taitung University, Taitung, Taiwan<br />

pengan@nttu.edu.tw<br />

ABSTRACT<br />

In 2004, Matouˇsek provided a fascinating combinatorial proof of the Kneser conjecture.<br />

Ziegler (2002) extended the scope of Matouˇsek’s approach, by establishing a combinatorial<br />

proof of the hypergraph coloring theorem of Dol’nikov (1981). He also provided a<br />

combinatorial proof of Schrijver’s theorem (1978). In this paper, we prove some coloring<br />

theorems of Kneser hypergraphs via the Octahedral Tucker’s lemma <strong>and</strong> the Octahedral<br />

Fan’s lemma.<br />

KEYWORDS: Kneser hypergraphs, Dol’nikov theorem, Octahedral Tucker’s lemma,<br />

Octahedral Fan’s lemma

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