## Abstract The (__d__,1)‐total number $\lambda \_{d}^{T}(G)$ of a graph __G__ is the width of the smallest range of integers that suffices to label the vertices and the edges of __G__ so that no two adjacent vertices have the same color, no two incident edges have the same color, and the distance
Improper choosability of graphs and maximum average degree
✍ Scribed by Frédéric Havet; Jean-Sébastien Sereni
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 174 KB
- Volume
- 52
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Improper choosability of planar graphs has been widely studied. In particular, Škrekovski investigated the smallest integer g~k~ such that every planar graph of girth at least g~k~ is k‐improper 2‐choosable. He proved [9] that 6 ≤ g~1~ ≤ 9; 5 ≤ g~2~ ≤ 7; 5 ≤ g~3~ ≤ 6; and ∀ k ≥ 4, g~k~ = 5. In this article, we study the greatest real M(k, l) such that every graph of maximum average degree less than M(k, l) is k‐improper l‐choosable. We prove that if l ≥ 2 then $M(k, l) \geq l + {l {\rm k} \over {l+k}}$. As a corollary, we deduce that g~1~ ≤ 8 and g~2~ ≤ 6, and we obtain new results for graphs of higher genus. We also provide an upper bound for M(k, l). This implies that for any fixed l, $M(k,l) \displaystyle\mathop{\longrightarrow}_{k \rightarrow \infty}{2l}$. © 2006 Wiley Periodicals, Inc. J Graph Theory 52: 181–199, 2006
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