Results 31 to 40 of about 258 (128)

Homomorphism and sigma polynomials

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 18, Issue 4, Page 653-658, 1995., 1995
By establishing a connection between the sigma polynomial and the homomorphism polynomial, many of the proofs for computing the sigma polynmial are simplified, the homomorphism polynomial can be identified for several new classes of graphs, and progress can be made on identifying homomorphism polynomials.
Richard Alan Gillman
wiley   +1 more source

Radio Number Of Wheel Like Graphs

open access: yes, 2011
In this paper we establish the radio number for Flower Wheel graph (F Wk n), k-Wheel graph (kW ) and Joint-Wheel graph(W Hn). AMS Subject classification: 05C78 (05C15)
A. A. Bhatti∗, Aster Nisar∗, Maria Kanwal∗   +1 more
core   +1 more source

Burnside Chromatic Polynomials of Group-Invariant Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2023
We introduce the Burnside chromatic polynomial of a graph that is invariant under a group action. This is a generalization of the Q-chromatic function Zaslavsky introduced for gain graphs.
White Jacob A.
doaj   +1 more source

Homomorphisms and related contractions of graphs

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 11, Issue 1, Page 95-100, 1988., 1986
For every homomorphism ϕ of a graph G there exists a contraction θϕ on , the complement of G. Here we study the graph equation . In the course of our work we show that Hadwiger′s Conjecture is true for every self‐complementary graph.
Robert D. Girse, Richard A. Gillman
wiley   +1 more source

Homomorphisms of complete n‐partite graphs

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 9, Issue 1, Page 193-195, 1986., 1985
It is shown that for every homomorphism ϕ of a graph G there exists a contraction θϕ on , the complement of G, such that if and only if G is a complete n‐partite graph.
Robert D. Girse
wiley   +1 more source

Generalized Ramsey numbers for paths in 2‐chromatic graphs

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 9, Issue 2, Page 273-276, 1986., 1985
Chung and Liu have defined the d‐chromatic Ramsey number as follows. Let 1 ≤ d ≤ c and let . Let 1, 2, …, t be the ordered subsets of d colors chosen from c distinct colors. Let G1, G2, …, Gt be graphs. The d‐chromatic Ramsey number denoted by is defined as the least number p such that, if the edges of the complete graph Kp are colored in any fashion ...
R. Meenakshi, P. S. Sundararaghavan
wiley   +1 more source

Relaxed DP-Coloring and another Generalization of DP-Coloring on Planar Graphs without 4-Cycles and 7-Cycles

open access: yesDiscussiones Mathematicae Graph Theory, 2023
DP-coloring is generalized via relaxed coloring and variable degeneracy in [P. Sittitrai and K. Nakprasit, Su cient conditions on planar graphs to have a relaxed DP-3-coloring, Graphs Combin. 35 (2019) 837–845], [K.M. Nakprasit and K.
Sribunhung Sarawute   +3 more
doaj   +1 more source

A New Kind of Dominated Coloring of Some Special Graphs

open access: yesJournal of Mathematics, Volume 2026, Issue 1, 2026.
This paper introduces the concept of locating‐dominated coloring, a new graph coloring parameter that merges the properties of dominated coloring and locating coloring. For a connected graph G, a locating‐dominated coloring is defined as a proper dominated k‐coloring of G using an ordered partition of V(G) to k‐color classes Π = (C1, C2, …, Ck) such ...
F. Poryousefi   +3 more
wiley   +1 more source

On the structure of a triangle‐free infinite‐chromatic graph of Gyarfas

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 6, Issue 2, Page 279-283, 1983., 1982
Gyárfás has recently constructed an elegant new example of a triangle‐free infinite graph G with infinite chromatic number. We analyze its structure by studying the properties of a nested family of subgraphs Gn whose union is G.
Larry Eggan, Frank Harary
wiley   +1 more source

b-Coloring of the Mycielskian of Some Classes of Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2022
The b-chromatic number b(G) of a graph G is the maximum k for which G has a proper vertex coloring using k colors such that each color class contains at least one vertex adjacent to a vertex of every other color class.
Raj S. Francis, Gokulnath M.
doaj   +1 more source

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