scholarly journals On-Line List Colouring of Random Graphs

Author(s):  
Alan Frieze ◽  
Dieter Mitsche ◽  
Xavier Pérez-Giménez ◽  
Paweł Prałat
Keyword(s):  
10.37236/5003 ◽  
2015 ◽  
Vol 22 (2) ◽  
Author(s):  
Alan Frieze ◽  
Dieter Mitsche ◽  
Xavier Pérez-Giménez ◽  
Paweł Prałat

In this paper, the on-line list colouring of binomial random graphs $\mathcal{G}(n,p)$ is studied. We show that the on-line choice number of $\mathcal{G}(n,p)$ is asymptotically almost surely asymptotic to the chromatic number of $\mathcal{G}(n,p)$, provided that the average degree $d=p(n-1)$ tends to infinity faster than $(\log \log n)^{1/3} (\log n)^2 n^{2/3}$. For sparser graphs, we are slightly less successful; we show that if $d \ge (\log n)^{2+\epsilon}$ for some $\epsilon>0$, then the on-line choice number is larger than the chromatic number by at most a multiplicative factor of $C$, where $C \in [2,4]$, depending on the range of $d$. Also, for $d=O(1)$, the on-line choice number is by at most a multiplicative constant factor larger than the chromatic number.


2012 ◽  
Vol 33 (5) ◽  
pp. 872-883 ◽  
Author(s):  
Po-Yi Huang ◽  
Tsai-Lien Wong ◽  
Xuding Zhu
Keyword(s):  

10.37236/2050 ◽  
2012 ◽  
Vol 19 (1) ◽  
Author(s):  
Seog-Jin Kim ◽  
Young Soo Kwon ◽  
Daphne Der-Fen Liu ◽  
Xuding Zhu

The Ohba Conjecture says that every graph $G$ with $|V(G)| \le 2 \chi(G)+1$ is chromatic choosable. This paper studies an on-line version of Ohba Conjecture. We prove that unlike the off-line case, for $k \ge 3$, the complete multipartite graph $K_{2\star (k-1), 3}$ is not on-line chromatic-choosable. Based on this result, the on-line version of Ohba Conjecture is modified as follows: Every graph $G$ with $|V(G)| \le 2 \chi(G)$ is on-line chromatic choosable. We present an explicit strategy to show  that for any positive integer $k$, the graph $K_{2\star k}$ is on-line chromatic-choosable.  We then present a minimal function $g$ for which the graph $K_{2 \star (k-1), 3}$ is on-line $g$-choosable.


2003 ◽  
Vol 211 ◽  
pp. 419-420 ◽  
Author(s):  
Derek Homeier ◽  
Peter H. Hauschildt ◽  
France Allard

We have updated our PHOENIX model atmospheres and theoretical spectra for ultracool dwarfs with new opacity data for methane based on line strength predictions with the STDS software. By extending the line list to rotational levels of J = 40 we can significantly improve the shape of the near-IR absorption features of CH4, and in addition find an enhanced blanketing effect, resulting in up to 50% more flux emerging in the J band than seen in previous models, which may thus contribute to the brightening in J and blue IR colors observed in T dwarfs.


10.37236/216 ◽  
2009 ◽  
Vol 16 (1) ◽  
Author(s):  
Xuding Zhu

This paper studies on-line list colouring of graphs. It is proved that the on-line choice number of a graph $G$ on $n$ vertices is at most $\chi(G) \ln n+1$, and the on-line $b$-choice number of $G$ is at most ${e\chi(G)-1\over e-1} (b-1+ \ln n)+b$. Suppose $G$ is a graph with a given $\chi(G)$-colouring of $G$. Then for any $(\chi(G) \ln n +1)$-assignment $L$ of $G$, we give a polynomial time algorithm which constructs an $L$-colouring of $G$. For any $({e\chi(G)-1\over e-1} (b-1+ \ln n)+b)$-assignment $L$ of $G$, we give a polynomial time algorithm which constructs an $(L,b)$-colouring of $G$. We then characterize all on-line $2$-choosable graphs. It is also proved that a complete bipartite graph of the form $K_{3,q}$ is on-line $3$-choosable if and only if it is $3$-choosable, but there are graphs of the form $K_{6,q}$ which are $3$-choosable but not on-line $3$-choosable. Some open questions concerning on-line list colouring are posed in the last section.


2016 ◽  
Vol 205 ◽  
pp. 109-125
Author(s):  
Daniel C. McDonald
Keyword(s):  

1997 ◽  
Vol 23 (1) ◽  
pp. 195-205 ◽  
Author(s):  
Boris Pittel ◽  
Robert S. Weishaar
Keyword(s):  

10.37236/448 ◽  
2010 ◽  
Vol 17 (1) ◽  
Author(s):  
Uwe Schauz

We study the list coloring number of $k$-uniform $k$-partite hypergraphs. Answering a question of Ramamurthi and West, we present a new upper bound which generalizes Alon and Tarsi's bound for bipartite graphs, the case $k=2$. Our results hold even for paintability (on" line list colorability). To prove this additional strengthening, we provide a new subject"=specific version of the Combinatorial Nullstellensatz.


Sign in / Sign up

Export Citation Format

Share Document