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arXiv math/9906011math.CO
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列表着色中的一些概念

Some concepts in list coloring

Ch. Eslahchi, M. Ghebleh, H. Hajiabolhassan

摘要:

本文研究了唯一列表可着色图.一个图G被称为是唯一k-列表可着色的,如果它允许一个k-列表分配,从该分配G有一个唯一的列表着色。G不是唯一k-列表可染的最小k称为G的M-数。本文证明了任何无三角形且色数为色数k+1的图都是唯一k-列表可染的。给出了图的M-数的一个界,并利用这个界证明了每个可平面图的M-数至多为4。在图中引入了列表临界性,刻画了所有3-列表临界图.证明了每个$χ_\ell$ -临界图都是$χ'$ -临界图,并证明了这个猜想与著名的列表着色猜想是等价的.

英文摘要:

In this paper uniquely list colorable graphs are studied. A graph G is called to be uniquely k-list colorable if it admits a k-list assignment from which G has a unique list coloring. The minimum k for which G is not uniquely k-list colorable is called the M-number of G. We show that every triangle-free uniquely vertex colorable graph with chromatic number k+1, is uniquely k-list colorable. A bound for the M-number of graphs is given, and using this bound it is shown that every planar graph has M-number at most 4. Also we introduce list criticality in graphs and characterize all 3-list critical graphs. It is conjectured that every $χ_\ell$-critical graph is $χ'$-critical and the equivalence of this conjecture to the well known list coloring conjecture is shown.

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