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Related papers: List chromatic numbers and singular compactness

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We study the list-chromatic number and the coloring number of graphs, especially uncountable graphs. We show that the coloring number of a graph coincides with its list-chromatic number provided that the diamond principle holds. Under the…

Logic · Mathematics 2021-12-30 Toshimichi Usuba

We prove analogs of Brooks' Theorem for the list-distinguishing chromatic number of different classes of simple finite connected graphs. Moreover, we determine two upper bounds for the list-distinguishing chromatic number of a graph G in…

Combinatorics · Mathematics 2025-07-23 Amitayu Banerjee , Zalán Molnár , Alexa Gopaulsingh

We show that, given an infinite cardinal $\mu$, a graph has colouring number at most $\mu$ if and only if it contains neither of two types of subgraph. We also show that every graph with infinite colouring number has a well-ordering of its…

Combinatorics · Mathematics 2018-07-05 Nathan Bowler , Johannes Carmesin , Péter Komjáth , Christian Reiher

In this paper, we try to determine exact or bounds on the choosability, or list chromatic numbers of some Cayley graphs, typically some Unitary Cayley graphs and Cayley graphs on Dihedral groups.

Combinatorics · Mathematics 2024-02-27 Prajnanaswaroopa S

We prove that for any regular kappa and mu > kappa below the first fix point (lambda = aleph_lambda) above kappa, there is a graph with chromatic number > kappa, and mu^kappa nodes but every subgraph of cardinality < mu has chromatic number…

Logic · Mathematics 2013-02-20 Saharon Shelah

We show that the existence of a universal countably chromatic graph of size $\aleph_1$ together with the failure of continuum hypothesis is consistent. The proof is a forcing iteration of strongly proper ccc posets. The construction works…

Logic · Mathematics 2025-11-12 Siiri Kivimäki

In this paper we find chromatic numbers of distance graphs $G(n,3,2)$ for infinitely many n. Also we improve upper bound for $\chi(G(n,r,s))$ in large part of cases.

Combinatorics · Mathematics 2016-08-08 D. Zakharov

The set of semialgebraic graphs having countable list-chromatic numbers is characterized. Some other related sets of graphs having countable list-chromatic numbers also are.

Combinatorics · Mathematics 2015-05-25 James H. Schmerl

Erd\H{o}s proved that there are graphs with arbitrarily large girth and chromatic number. We study the extension of this for generalized chromatic numbers.

Combinatorics · Mathematics 2007-05-23 Béla Bollobás , Douglas B. West

In 2006, Collins and Trenk obtained a general sharp upper bound for the distinguishing chromatic number of a connected graph. Inspired by Catlin's combinatorial techniques from 1978, we establish improved upper bounds for classes of…

Combinatorics · Mathematics 2025-09-16 Amitayu Banerjee

We give an upper bound on the list chromatic number of a 2-colorable hypergraph which generalizes the bound of Schauz on $k$-partite $k$-uniform hypergraphs. It makes sense for sparse hypergraphs: in particular we show that a $k$-uniform…

Combinatorics · Mathematics 2021-02-05 Danila Cherkashin , Alexey Gordeev

In the paper we give a lower bound for the number of vertices of a given graph using its chromatic number. We find the graphs for which this bound is exact. The results are applied in the theory of Foklman numbers.

Combinatorics · Mathematics 2010-02-24 Nedyalko Dimov Nenov

We consider the robust chromatic number $\chi_1(G)$ of planar graphs $G$ and show that there exists an infinite family of planar graphs $G$ with $\chi_1(G) = 3$, thus solving a recent problem of Bacs\'{o}~et~al. (The robust chromatic number…

Combinatorics · Mathematics 2024-12-24 František Kardoš , Borut Lužar , Roman Soták

Ohba has conjectured \cite{ohb} that if the graph $G$ has $2\chi(G)+1$ or fewer vertices then the list chromatic number and chromatic number of $G$ are equal. In this paper we prove that this conjecture is asymptotically correct. More…

Combinatorics · Mathematics 2007-05-23 Bruce Reed , Benny Sudakov

A graph is called to be uniquely list colorable, if it admits a list assignment which induces a unique list coloring. We study uniquely list colorable graphs with a restriction on the number of colors used. In this way we generalize a…

Combinatorics · Mathematics 2008-01-03 Y. G. Ganjali , M. Ghebleh , H. Hajiabolhassan , M. Mirzazadeh , B. S. Sadjad

Komjath studied the list chromatic number of infinite graphs and introduced the notion of restricted list chromatic number. For a graph $X=(V_X,E_X)$ and a cardinal $\kappa$, we say that $X$ is restricted list colorable for $\kappa$ if for…

Logic · Mathematics 2025-12-17 Yusuke Hayashi

We introduce a notion of color-criticality in the context of chromatic-choosability. We define a graph $G$ to be strong $k$-chromatic-choosable if $\chi(G) = k$ and every $(k-1)$-assignment for which $G$ is not list-colorable has the…

Combinatorics · Mathematics 2018-08-08 Hemanshu Kaul , Jeffrey A. Mudrock

We show that the strong odd chromatic number on any proper minor-closed graph class is bounded by a constant. We almost determine the smallest such constant for outerplanar graphs.

Combinatorics · Mathematics 2025-05-06 Miriam Goetze , Fabian Klute , Kolja Knauer , Irene Parada , Juan Pablo Peña , Torsten Ueckerdt

We prove that reflection of the coloring number of graphs is consistent with non-reflection of the chromatic number. Moreover, it is proved that incompactness for the chromatic number of graphs (with arbitrarily large gaps) is compatible…

Logic · Mathematics 2017-08-24 Chris Lambie-Hanson , Assaf Rinot

This paper investigates when countable graphs have a finite or an infinite chromatic number through model theoretic methods. For Fra\"{i}ss\'{e} limits, we show that instability forces the chromatic number to be infinite, yielding a…

Logic · Mathematics 2026-02-25 Hirotaka Kikyo , Koitaro Nakaura , Akito Tsuboi
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