Inverse chromatic number problems in interval and permutation graphs

2015 ◽  
Vol 243 (3) ◽  
pp. 763-773
Author(s):  
Yerim Chung ◽  
Jean-François Culus ◽  
Marc Demange
Keyword(s):  
Chromatic Number ◽  
Permutation Graphs

scholarly journals On the Chromatic Number of Matching Kneser Graphs

2019 ◽  
Vol 29 (1) ◽  
pp. 1-21
Author(s):  
Meysam Alishahi ◽  
Hajiabolhassan Hossein
Keyword(s):  
Lower Bound ◽  
Chromatic Number ◽  
Large Family ◽  
Permutation Graphs ◽  
Kneser Graph ◽  
Ulam Theorem ◽  
Turán Number ◽  
Vertex Set ◽  
Kneser Graphs ◽  
Host Graph

AbstractIn an earlier paper, the present authors (2015) introduced the altermatic number of graphs and used Tucker’s lemma, an equivalent combinatorial version of the Borsuk–Ulam theorem, to prove that the altermatic number is a lower bound for chromatic number. A matching Kneser graph is a graph whose vertex set consists of all matchings of a specified size in a host graph and two vertices are adjacent if their corresponding matchings are edge-disjoint. Some well-known families of graphs such as Kneser graphs, Schrijver graphs and permutation graphs can be represented by matching Kneser graphs. In this paper, unifying and generalizing some earlier works by Lovász (1978) and Schrijver (1978), we determine the chromatic number of a large family of matching Kneser graphs by specifying their altermatic number. In particular, we determine the chromatic number of these matching Kneser graphs in terms of the generalized Turán number of matchings.

(G1,G2)-permutation graphs

2015 ◽  
Vol 07 (04) ◽  
pp. 1550051 ◽  
Author(s):  
Behrooz Bagheri Gh.
Keyword(s):  
Large Class ◽  
Chromatic Number ◽  
Edge Connectivity ◽  
Permutation Graph ◽  
Permutation Graphs ◽  
Labeled Graph ◽  
Total Distance ◽  
Labeled Graphs

Let [Formula: see text] and [Formula: see text] be two labeled graphs of order [Formula: see text]. For any permutation [Formula: see text] the [Formula: see text]-permutation graph of labeled graphs [Formula: see text] and [Formula: see text] is the union of [Formula: see text] and [Formula: see text] together with the edges joining the vertex [Formula: see text] to the vertex [Formula: see text]. This operation on graphs is useful to produce a large class of networks with approximately the same properties as one of the original networks or even smaller. In this work we consider some properties of the permutation graph [Formula: see text], for labeled graph [Formula: see text] and [Formula: see text] of the same order. We provide bounds for the parameters radius, diameter, total distance, connectivity, edge-connectivity, chromatic number, and edge-chromatic number.

Packing Chromatic Number of Cycle Related Graphs

2014 ◽  
Vol 4 (1) ◽  
pp. 27
Author(s):  
Albert William ◽  
Roy Santiago ◽  
Indra Rajasingh
Keyword(s):  
Chromatic Number ◽  
Packing Chromatic Number

Packing coloring on subdivision-vertex and subdivision-edge join of cycle Cm with path Pn

2020 ◽  
pp. 627-634
Author(s):  
K. Rajalakshmi ◽  
M. Venkatachalam ◽  
M. Barani ◽  
D. Dafik
Keyword(s):  
Chromatic Number ◽  
Path Graph ◽  
Packing Chromatic Number ◽  
Cycle Graph

The packing chromatic number $\chi_\rho$ of a graph $G$ is the smallest integer $k$ for which there exists a mapping $\pi$ from $V(G)$ to $\{1,2,...,k\}$ such that any two vertices of color $i$ are at distance at least $i+1$. In this paper, the authors find the packing chromatic number of subdivision vertex join of cycle graph with path graph and subdivision edge join of cycle graph with path graph.

scholarly journals On metric chromatic number of comb product of ladder graph

2021 ◽  
Vol 1836 (1) ◽  
pp. 012026
Author(s):  
M Y Rohmatulloh ◽  
Slamin ◽  
A I Kristiana ◽  
Dafik ◽  
R Alfarisi
Keyword(s):  
Chromatic Number ◽  
Ladder Graph

scholarly journals On number of pendants in local antimagic chromatic number

2021 ◽  
pp. 1-10
Author(s):  
Gee-Choon Lau ◽  
Wai-Chee Shiu ◽  
Ho-Kuen Ng
Keyword(s):  
Chromatic Number
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