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Wyszukujesz frazę "chromatic index" wg kryterium: Temat


Wyświetlanie 1-15 z 15
Tytuł:
Relations between the domination parameters and the chromatic index of a graph
Autorzy:
Ulatowski, Włodzimierz
Powiązania:
https://bibliotekanauki.pl/articles/744471.pdf
Data publikacji:
2009
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
domination
domination parameters
chromatic index
Opis:
In this paper we show upper bounds for the sum and the product of the lower domination parameters and the chromatic index of a graph. We also present some families of graphs for which these upper bounds are achieved. Next, we give a lower bound for the sum of the upper domination parameters and the chromatic index. This lower bound is a function of the number of vertices of a graph and a new graph parameter which is defined here. In this case we also characterize graphs for which a respective equality holds.
Źródło:
Discussiones Mathematicae Graph Theory; 2009, 29, 3; 615-627
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the ρ-Edge Stability Number of Graphs
Autorzy:
Kemnitz, Arnfried
Marangio, Massimiliano
Powiązania:
https://bibliotekanauki.pl/articles/32361738.pdf
Data publikacji:
2022-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
edge stability number
line stability
invariant
chromatic edge stability index
chromatic index
edge coloring
Opis:
For an arbitrary invariant $ \rho(G) $ of a graph $G$ the $ \rho $-edge stability number $ es_\rho (G) $ is the minimum number of edges of $G$ whose removal results in a graph $ H \subseteq G $ with $ \rho (H) \ne \rho (G) $ or with $ E(H) = \emptyset $. In the first part of this paper we give some general lower and upper bounds for the $ \rho $-edge stability number. In the second part we study the $ \chi^' $-edge stability number of graphs, where $ \chi^' = \chi^' (G) $ is the chromatic index of $G$. We prove some general results for the so-called chromatic edge stability index $ es_{ \chi^′ } (G) $ and determine $ es_{ \chi^′ } (G) $ exactly for specific classes of graphs.
Źródło:
Discussiones Mathematicae Graph Theory; 2022, 42, 1; 249-262
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Upper Bounds for the Strong Chromatic Index of Halin Graphs
Autorzy:
Hu, Ziyu
Lih, Ko-Wei
Liu, Daphne Der-Fen
Powiązania:
https://bibliotekanauki.pl/articles/16647759.pdf
Data publikacji:
2018-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
strong edge-coloring
strong chromatic index
Halin graphs
Opis:
The strong chromatic index of a graph G, denoted by χ′s(G), is the minimum number of vertex induced matchings needed to partition the edge set of G. Let T be a tree without vertices of degree 2 and have at least one vertex of degree greater than 2. We construct a Halin graph G by drawing T on the plane and then drawing a cycle C connecting all its leaves in such a way that C forms the boundary of the unbounded face. We call T the characteristic tree of G. Let G denote a Halin graph with maximum degree Δ and characteristic tree T. We prove that χ′s(G) ⩽ 2Δ + 1 when Δ ⩾ 4. In addition, we show that if Δ = 4 and G is not a wheel, then χ′s(G) ⩽ χ′s(T) + 2. A similar result for Δ = 3 was established by Lih and Liu [21].
Źródło:
Discussiones Mathematicae Graph Theory; 2018, 38, 1; 5-26
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Upper Bounds for the Strong Chromatic Index of Halin Graphs
Autorzy:
Hu, Ziyu
Lih, Ko-Wei
Liu, Daphne Der-Fen
Powiązania:
https://bibliotekanauki.pl/articles/31342445.pdf
Data publikacji:
2018-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
strong edge-coloring
strong chromatic index
Halin graphs
Opis:
The strong chromatic index of a graph $G$, denoted by $ \chi_s^′ (G) $, is the minimum number of vertex induced matchings needed to partition the edge set of $G$. Let $T$ be a tree without vertices of degree 2 and have at least one vertex of degree greater than 2. We construct a Halin graph $G$ by drawing $T$ on the plane and then drawing a cycle $C$ connecting all its leaves in such a way that $C$ forms the boundary of the unbounded face. We call $T$ the characteristic tree of $G$. Let $G$ denote a Halin graph with maximum degree $ \Delta $ and characteristic tree $T$. We prove that $ \chi_s^′ (G) \le 2 \Delta + 1 $ when $ \Delta \ge 4 $. In addition, we show that if $ \Delta = 4 $ and $G$ is not a wheel, then $ \chi_s^′ (G) \le \chi_s^′ (T) + 2 $. A similar result for $ \Delta = 3 $ was established by Lih and Liu [21].
Źródło:
Discussiones Mathematicae Graph Theory; 2018, 38, 1; 5-26
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some maximum multigraphs and edge/vertex distance colourings
Autorzy:
Skupień, Zdzisław
Powiązania:
https://bibliotekanauki.pl/articles/971931.pdf
Data publikacji:
1995
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
(strong) chromatic index
chromatic number
matching
hypercube
error-correcting code
asymptotics
Opis:
Shannon-Vizing-type problems concerning the upper bound for a distance chromatic index of multigraphs G in terms of the maximum degree Δ(G) are studied. Conjectures generalizing those related to the strong chromatic index are presented. The chromatic d-index and chromatic d-number of paths, cycles, trees and some hypercubes are determined. Among hypercubes, however, the exact order of their growth is found.
Źródło:
Discussiones Mathematicae Graph Theory; 1995, 15, 1; 89-106
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On locally irregular decompositions of subcubic graphs
Autorzy:
Baudon, O.
Bensmail, J.
Hocquard, H.
Senhaji, M.
Sopena, E.
Powiązania:
https://bibliotekanauki.pl/articles/254905.pdf
Data publikacji:
2018
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
locally irregular edge-colouring irregular chromatic index
subcubic graphs
Opis:
A graph G is locally irregular if every two adjacent vertices of G have different degrees. A locally irregular decomposition of G is a partition E1,.. . , Ek of E(G) such that each G[Ei] is locally irregular. Not all graphs admit locally irregular decompositions, but for those who are decomposable, in that sense, it was conjectured by Baudon, Bensmail, Przybyło and Woźniak that they decompose into at most 3 locally irregular graphs. Towards that conjecture, it was recently proved by Bensmail, Merker and Thomassen that every decomposable graph decomposes into at most 328 locally irregular graphs. We here focus on locally irregular decompositions of subcubic graphs, which form an important family of graphs in this context, as all non-decomposable graphs are subcubic. As a main result, we prove that decomposable subcubic graphs decompose into at most 5 locally irregular graphs, and only at most 4 when the maximum average degree is less than 12/5. We then consider weaker decompositions, where subgraphs can also include regular connected components, and prove the relaxations of the conjecture above for subcubic graphs.
Źródło:
Opuscula Mathematica; 2018, 38, 6; 795-817
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Proper (Strong) Rainbow Connection of Graphs
Autorzy:
Jiang, Hui
Li, Wenjing
Li, Xueliang
Magnant, Colton
Powiązania:
https://bibliotekanauki.pl/articles/32083886.pdf
Data publikacji:
2021-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
proper (strong) rainbow connection number
Cartesian product
chromatic index
Opis:
A path in an edge-colored graph $G$ is called a rainbow path if no two edges on the path have the same color. The graph $G$ is called rainbow connected if between every pair of distinct vertices of $G$, there is a rainbow path. Recently, Johnson et al. considered this concept with the additional requirement that the coloring of $G$ is proper. The proper rainbow connection number of $G$, denoted by $prc(G)$, is the minimum number of colors needed to properly color the edges of $G$ so that $G$ is rainbow connected. Similarly, the proper strong rainbow connection number of $G$, denoted by $psrc(G)$, is the minimum number of colors needed to properly color the edges of $G$ such that for any two distinct vertices of $G$, there is a rainbow geodesic (shortest path) connecting them. In this paper, we characterize those graphs with proper rainbow connection numbers equal to the size or within 1 of the size. Moreover, we completely solve a question proposed by Johnson et al. by proving that if \(G = K_{p1} \Box \dots \Box K_{pn}\), where $n≥ 1$, and $p_1, . . ., p_n>1$ are integers, then $prc(G) = psrc(G) = χ^′(G)$, where $χ^′(G)$ denotes the chromatic index of $G$. Finally, we investigate some suffcient conditions for a graph $G$ to satisfy $prc(G) = rc(G)$, and make some slightly positive progress by using a relation between $rc(G)$ and the girth of the graph.
Źródło:
Discussiones Mathematicae Graph Theory; 2021, 41, 2; 469-479
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Localization of jumps of the point-distinguishing chromatic index of $K_{n,n}
Autorzy:
Horňák, Mirko
Soták, Roman
Powiązania:
https://bibliotekanauki.pl/articles/972023.pdf
Data publikacji:
1997
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
Point-distinguishing chromatic index
colour set
complete equibipartite graph
Opis:
The point-distinguishing chromatic index of a graph represents the minimum number of colours in its edge colouring such that each vertex is distinguished by the set of colours of edges incident with it. Asymptotic information on jumps of the point-distinguishing chromatic index of $K_{n,n}$ is found.
Źródło:
Discussiones Mathematicae Graph Theory; 1997, 17, 2; 243-251
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Star Chromatic Index of Generalized Petersen Graphs
Autorzy:
Zhu, Enqiang
Shao, Zehui
Powiązania:
https://bibliotekanauki.pl/articles/32083878.pdf
Data publikacji:
2021-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
star edge-coloring
star chromatic index
generalized Petersen graph
Opis:
The star $k$-edge-coloring of graph $G$ is a proper edge coloring using $k$ colors such that no path or cycle of length four is bichromatic. The minimum number $k$ for which $G$ admits a star $k$-edge-coloring is called the star chromatic index of $G$, denoted by $χ_s^′(G)$. Let $GCD(n, k)$ be the greatest common divisor of $n$ and $k$. In this paper, we give a necessary and sufficient condition of $χ_s^′(P(n, k)) = 4$ for a generalized Petersen graph $P(n, k)$ and show that “almost all” generalized Petersen graphs have a star 5-edge-colorings. Furthermore, for any two integers $k$ and $n(≥2k + 1)$ such that $GCD(n, k) ≥ 3, P (n, k)$ has a star 5-edge-coloring, with the exception of the case that $GCD(n, k) = 3$, $k ≠ GCD(n, k)$ and \(\frac{n}{3}≡1(mod3)\).
Źródło:
Discussiones Mathematicae Graph Theory; 2021, 41, 2; 427-439
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Edge colorings and total colorings of integer distance graphs
Autorzy:
Kemnitz, Arnfried
Marangio, Massimiliano
Powiązania:
https://bibliotekanauki.pl/articles/743555.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
integer distance graph
chromatic number
choice number
chromatic index
choice index
total chromatic number
total choice number
Opis:
An integer distance graph is a graph G(D) with the set Z of integers as vertex set and two vertices u,v ∈ Z are adjacent if and only if |u-v| ∈ D where the distance set D is a subset of the positive integers N. In this note we determine the chromatic index, the choice index, the total chromatic number and the total choice number of all integer distance graphs, and the choice number of special integer distance graphs.
Źródło:
Discussiones Mathematicae Graph Theory; 2002, 22, 1; 149-158
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adjacent vertex distinguishing edge colorings of the direct product of a regular graph by a path or a cycle
Autorzy:
Frigerio, Laura
Lastaria, Federico
Salvi, Norma
Powiązania:
https://bibliotekanauki.pl/articles/743981.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
chromatic index
adjacent vertex distinguishing edge coloring
direct product
matching
Opis:
In this paper we investigate the minimum number of colors required for a proper edge coloring of a finite, undirected, regular graph G in which no two adjacent vertices are incident to edges colored with the same set of colors. In particular, we study this parameter in relation to the direct product of G by a path or a cycle.
Źródło:
Discussiones Mathematicae Graph Theory; 2011, 31, 3; 547-557
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vertex-distinguishing edge-colorings of linear forests
Autorzy:
Cichacz, Sylwia
Przybyło, Jakub
Powiązania:
https://bibliotekanauki.pl/articles/744522.pdf
Data publikacji:
2010
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
irregular edge-coloring
vertex-distinguishing edge-coloring
point-distinguishing chromatic index
Opis:
In the PhD thesis by Burris (Memphis (1993)), a conjecture was made concerning the number of colors c(G) required to edge-color a simple graph G so that no two distinct vertices are incident to the same multiset of colors. We find the exact value of c(G) - the irregular coloring number, and hence verify the conjecture when G is a vertex-disjoint union of paths. We also investigate the point-distinguishing chromatic index, χ₀(G), where sets, instead of multisets, are required to be distinct, and determine its value for the same family of graphs.
Źródło:
Discussiones Mathematicae Graph Theory; 2010, 30, 1; 95-103
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Strong Edge-Coloring Of Planar Graphs
Autorzy:
Song, Wen-Yao
Miao, Lian-Ying
Powiązania:
https://bibliotekanauki.pl/articles/31341618.pdf
Data publikacji:
2017-11-27
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
strong edge-coloring
strong chromatic index
planar graph
dis- charging method
Opis:
A strong edge-coloring of a graph is a proper edge-coloring where each color class induces a matching. We denote by $ \chi_s^' (G) $ the strong chromatic index of $G$ which is the smallest integer $k$ such that $G$ can be strongly edge-colored with $k$ colors. It is known that every planar graph $G$ has a strong edge-coloring with at most $ 4 \Delta (G) + 4 $ colors [R.J. Faudree, A. Gyárfás, R.H. Schelp and Zs. Tuza, The strong chromatic index of graphs, Ars Combin. 29B (1990) 205–211]. In this paper, we show that if $G$ is a planar graph with $ g \ge 5$, then $ \chi_s^' (G) \le 4 \Delta (G) − 2 $ when $ \Delta (G) \ge 6 $ and $ \chi_s^' (G) \le 19 $ when $ \Delta (G) = 5 $, where $g$ is the girth of $G$.
Źródło:
Discussiones Mathematicae Graph Theory; 2017, 37, 4; 845-857
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Three edge-coloring conjectures
Autorzy:
Schelp, Richard
Powiązania:
https://bibliotekanauki.pl/articles/743559.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
edge-coloring
Ramsey number
vertex-distinguishing edge-coloring
strong chromatic index
balanced edge-coloring
local coloring
mean coloring
Opis:
The focus of this article is on three of the author's open conjectures. The article itself surveys results relating to the conjectures and shows where the conjectures are known to hold.
Źródło:
Discussiones Mathematicae Graph Theory; 2002, 22, 1; 173-182
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
General multiplicative Zagreb indices of graphs with given clique number
Autorzy:
Vetrik, Tomas
Balachandran, Selvaraj
Powiązania:
https://bibliotekanauki.pl/articles/255259.pdf
Data publikacji:
2019
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
clique number
multiplicative Zagreb index
chromatic number
Opis:
We obtain lower and upper bounds on general multiplicative Zagreb indices for graphs of given clique number and order. Bounds on the basic multiplicative Zagreb indices and on the multiplicative sum Zagreb index follow from our results. We also determine graphs with the smallest and the largest indices.
Źródło:
Opuscula Mathematica; 2019, 39, 3; 433-446
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-15 z 15

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