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Wyszukujesz frazę "total chromatic number" wg kryterium: Temat


Wyświetlanie 1-8 z 8
Tytuł:
On local antimagic total labeling of complete graphs amalgamation
Autorzy:
Lau, Gee-Choon
Shiu, Wai-Chee
Powiązania:
https://bibliotekanauki.pl/articles/29519348.pdf
Data publikacji:
2023
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
local antimagic (total) chromatic number
amalgamation
complete graph
Opis:
Let G = (V,E) be a connected simple graph of order p and size q. A graph G is called local antimagic (total) if G admits a local antimagic (total) labeling. A bijection g : E → {1, 2, . . . , q} is called a local antimagic labeling of G if for any two adjacent vertices u and v, we have $ g^+ (u) \ne g^+ (v) $, where $ g^+ (u) = \Sigma_{e∈E(u)} \text{ } g(e) $, and E(u) is the set of edges incident to u. Similarly, a bijection f : V (G)∪E(G) → {1, 2, . . . , p+q} is called a local antimagic total labeling of G if for any two adjacent vertices u and v, we have $ w_f (u) \ne w_f (v) $, where $ w_f (u) = f(u) + \Sigma_{e∈E(u)} f(e) $. Thus, any local antimagic (total) labeling induces a proper vertex coloring of G if vertex v is assigned the color $g^+ (v) $ (respectively, $ w_f (u) $). The local antimagic (total) chromatic number, denoted $χ_\text{la } (G) $ (respectively $χ_\text{lat } (G) $ ), is the minimum number of induced colors taken over local antimagic (total) labeling of G. In this paper, we determined $ χ_\text{lat } (G) $ where G is the amalgamation of complete graphs. Consequently, we also obtained the local antimagic (total) chromatic number of the disjoint union of complete graphs, and the join of $ K_1 $ and amalgamation of complete graphs under various conditions. An application of local antimagic total chromatic number is also given.
Źródło:
Opuscula Mathematica; 2023, 43, 3; 429-453
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chromatic Properties of the Pancake Graphs
Autorzy:
Konstantinova, Elena
Powiązania:
https://bibliotekanauki.pl/articles/31341647.pdf
Data publikacji:
2017-08-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
Pancake graph
Cayley graphs
symmetric group
chromatic number
total chromatic number
Opis:
Chromatic properties of the Pancake graphs Pn, n ⩾ 2, that are Cayley graphs on the symmetric group Symn generated by prefix-reversals are investigated in the paper. It is proved that for any n ⩾ 3 the total chromatic number of Pn is n, and it is shown that the chromatic index of Pn is n − 1. We present upper bounds on the chromatic number of the Pancake graphs Pn, which improve Brooks’ bound for n ⩾ 7 and Katlin’s bound for n ⩽ 28. Algorithms of a total n-coloring and a proper (n − 1)-coloring are given.
Źródło:
Discussiones Mathematicae Graph Theory; 2017, 37, 3; 777-787
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Generalized Fractional and Circular Total Colorings of Graphs
Autorzy:
Kemnitz, Arnfried
Marangio, Massimiliano
Mihók, Peter
Oravcová, Janka
Soták, Roman
Powiązania:
https://bibliotekanauki.pl/articles/31339338.pdf
Data publikacji:
2015-08-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
graph property
(P,Q)-total coloring
circular coloring
fractional coloring
fractional (P,Q)-total chromatic number
circular (P,Q)- total chromatic number
Opis:
Let \( \mathcal{P} \) and \( \mathcal{Q} \) be additive and hereditary graph properties, $ r, s \in \mathbb{N}$, $ r \ge s $, and $ [\mathbb{Z}_r]^s $ be the set of all s-element subsets of $\mathbb{Z}_r $. An ($r$, $s$)-fractional (\( \mathcal{P} \),\( \mathcal{Q} \))-total coloring of $G$ is an assignment $ h : V (G) \cup E(G) \rightarrow [\mathbb{Z}_r]^s $ such that for each $ i \in \mathbb{Z}_r $ the following holds: the vertices of $G$ whose color sets contain color $i$ induce a subgraph of $G$ with property \( \mathcal{P} \), edges with color sets containing color $i$ induce a subgraph of $G$ with property \( \mathcal{Q} \), and the color sets of incident vertices and edges are disjoint. If each vertex and edge of $G$ is colored with a set of $s$ consecutive elements of $ \mathbb{Z}_r $ we obtain an ($r$, $s$)-circular (\( \mathcal{P} \),\( \mathcal{Q} \))-total coloring of $G$. In this paper we present basic results on ($r$, $s$)-fractional/circular (\( \mathcal{P} \),\( \mathcal{Q} \))-total colorings. We introduce the fractional and circular (\( \mathcal{P} \),\( \mathcal{Q}\))-total chromatic number of a graph and we determine this number for complete graphs and some classes of additive and hereditary properties.
Źródło:
Discussiones Mathematicae Graph Theory; 2015, 35, 3; 517-532
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Every graph is local antimagic total and its applications
Autorzy:
Lau, Gee-Choon
Schaffer, Karl
Shiu, Wai-Chee
Powiązania:
https://bibliotekanauki.pl/articles/29519430.pdf
Data publikacji:
2023
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
local antimagic (total) chromatic number
Cartesian product
join product
Opis:
Let $ G = (V, E) $ be a simple graph of order $ p $ and size $ q $. A graph $ G $ is called local antimagic (total) if $ G $ admits a local antimagic (total) labeling. A bijection $ g : E → {1, 2, . . . , q} $ is called a local antimagic labeling of $ G $ if for any two adjacent vertices $ u $ and $ v $, we have $g^+(u) ≠ g^+(v) $, where $ g^+(u) = \Sigma_{e∈E(u)} g(e) $, and $ E(u) $ is the set of edges incident to $ u $. Similarly, a bijection $f : V (G)∪E(G) → {1, 2, . . . , p+q} $ is called a local antimagic total labeling of $ G $ if for any two adjacent vertices $ u $ and $ v $, we have $ w_f (u) ≠ w_f (v) $, where $ w_f (u) = f(u) + \Sigma_{e∈E(u)} f(e) $. Thus, any local antimagic (total) labeling induces a proper vertex coloring of $ G $ if vertex $ v $ is assigned the color $ g^+ (v) $ (respectively, $ w_f (u) $). The local antimagic (total) chromatic number, denoted $ χ_{la} (G) $ (respectively $ χ_{lat} (G)$ ), is the minimum number of induced colors taken over local antimagic (total) labeling of $ G $. We provide a short proof that every graph $ G $ is local antimagic total. The proof provides sharp upper bound to $ χ_{lat} (G) $. We then determined the exact $ χ_{lat} (G) $, where $ G $ is a complete bipartite graph, a path, or the Cartesian product of two cycles. Consequently, the $ χ_{la} (G ∨ K_1) $ is also obtained. Moreover, we determined the $ χ_{la} (G ∨ K_1) $ and hence the $χ_{lat} (G) $ for a class of 2-regular graphs $ G $ (possibly with a path). The work of this paper also provides many open problems on $ χ_{lat} (G) $. We also conjecture that each graph $ G $ of order at least 3 has $ χ_{lat} (G) ≤ χ_{la} (G) $.
Źródło:
Opuscula Mathematica; 2023, 43, 6; 841-864
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
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:
Fractional (\( \mathcal{P} , \mathcal{Q} \))-Total List Colorings of Graphs
Autorzy:
Kemnitz, Arnfried
Mihók, Peter
Voigt, Margit
Powiązania:
https://bibliotekanauki.pl/articles/30146708.pdf
Data publikacji:
2013-03-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
graph property
total coloring
(P,Q)-total coloring
fractional coloring
fractional (P,Q)-total chromatic number
circular coloring
circular (P,Q)-total chromatic number
list coloring
(P,Q)-total (a
b)-list colorings
Opis:
Let $ r, s \in \mathbb{N}$, $r \ge s$, and \( \mathcal{P} \) and \( \mathcal{Q} \) be two additive and hereditary graph properties. A \( (P,Q) \)-total $(r, s)$-coloring of a graph $G = (V,E)$ is a coloring of the vertices and edges of $G$ by $s$-element subsets of $ \mathbb{Z}_r$ such that for each color $i$, $0 \le i \le r − 1$, the vertices colored by subsets containing $i$ induce a subgraph of $G$ with property \( \mathcal{P} \), the edges colored by subsets containing $i$ induce a subgraph of $G$ with property \( \mathcal{Q} \), and color sets of incident vertices and edges are disjoint. The fractional \( (\mathcal{P}, \mathcal{Q})\)-total chromatic number $ \chi_{f,P,Q}^{''}(G)$ of $G$ is defined as the infimum of all ratios $r//s$ such that $G$ has a \( ( \mathcal{P}, \mathcal{Q})\)-total $(r, s)$-coloring. A \( ( \mathcal{P}, \mathcal{Q} \)-total independent set $ T = V_T \cup E_T \subseteq V \cup E$ is the union of a set $V_T$ of vertices and a set $E_T$ of edges of $G$ such that for the graphs induced by the sets $V_T$ and $E_T$ it holds that \( G[ V_T ] \in \mathcal{ P } \), \( G[ E_T ] \in \mathcal{Q} \), and $ G[ V_T ] $ and $ G[ E_T ] $ are disjoint. Let \( T_{ \mathcal{P} , \mathcal{Q} } \) be the set of all \( (\mathcal{P} ,\mathcal{Q})\)-total independent sets of $G$. Let $L(x)$ be a set of admissible colors for every element $ x \in V \cup E $. The graph $G$ is called \( (\mathcal{P} , \mathcal{Q}) \)-total $(a, b)$-list colorable if for each list assignment $L$ with $|L(x)| = a$ for all $x \in V \cup E$ it is possible to choose a subset $ C(x) \subseteq L(x)$ with $|C(x)| = b$ for all $ x \in V \cup E$ such that the set $ T_i $ which is defined by $ T_i = {x \in V \cup E : i \in C(x) } $ belongs to \( T_{ \mathcal{P},\mathcal{Q}}\) for every color $i$. The \( (\mathcal{P}, \mathcal{Q})\)- choice ratio \( \text{chr}_{\mathcal{P},\mathcal{Q}}(G)\) of $G$ is defined as the infimum of all ratios $a//b$ such that $G$ is \( (\mathcal{P},\mathcal{Q})\)-total $(a, b)$-list colorable. We give a direct proof of \( \chi_{ f,\mathcal{P},\mathcal{Q} }^{ \prime \prime } (G) = \text{chr}_{ \mathcal{P} ,\mathcal{Q} }(G)\) for all simple graphs $G$ and we present for some properties \( \mathcal{P} \) and \( \mathcal{Q} \) new bounds for the \( (\mathcal{P}, \mathcal{Q})\)-total chromatic number and for the \((\mathcal{P},\mathcal{Q})\)-choice ratio of a graph $G$.
Źródło:
Discussiones Mathematicae Graph Theory; 2013, 33, 1; 167-179
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vertex-Distinguishing IE-Total Colorings of Complete Bipartite Graphs Km,N(m < n)
Autorzy:
Chen, Xiang’en
Gao, Yuping
Yao, Bing
Powiązania:
https://bibliotekanauki.pl/articles/30146641.pdf
Data publikacji:
2013-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
complete bipartite graphs
IE-total coloring
vertex-distinguishing IE-total coloring
vertex-distinguishing IE-total chromatic number
Opis:
Let G be a simple graph. An IE-total coloring f of G is a coloring of the vertices and edges of G so that no two adjacent vertices receive the same color. Let C(u) be the set of colors of vertex u and edges incident to u under f. For an IE-total coloring f of G using k colors, if C(u) ≠ C(v) for any two different vertices u and v of G, then f is called a k-vertex-distinguishing IE-total-coloring of G, or a k-VDIET coloring of G for short. The minimum number of colors required for a VDIET coloring of G is denoted by χievt(G), and is called vertex-distinguishing IE-total chromatic number or the VDIET chromatic number of G for short. VDIET colorings of complete bipartite graphs Km,n(m < n) are discussed in this paper. Particularly, the VDIET chromatic numbers of Km,n(1 ≤ m ≤ 7, m < n) as well as complete graphs Kn are obtained.
Źródło:
Discussiones Mathematicae Graph Theory; 2013, 33, 2; 289-306
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Total Graph of Mycielski Graphs, Central Graphs and Their Covering Numbers
Autorzy:
Patil, H.P.
Pandiya Raj, R.
Powiązania:
https://bibliotekanauki.pl/articles/30146583.pdf
Data publikacji:
2013-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
total graph
central graph
middle graph
Mycielski graph
independence number
covering number
edge independence number
edge covering number
chromatic number
achromatic number
Opis:
The technique of counting cliques in networks is a natural problem. In this paper, we develop certain results on counting of triangles for the total graph of the Mycielski graph or central graph of star as well as completegraph families. Moreover, we discuss the upper bounds for the number of triangles in the Mycielski and other well known transformations of graphs. Finally, it is shown that the achromatic number and edge-covering number of the transformations mentioned above are equated.
Źródło:
Discussiones Mathematicae Graph Theory; 2013, 33, 2; 361-371
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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