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Wyszukujesz frazę "lexicographic product" wg kryterium: Temat


Wyświetlanie 1-10 z 10
Tytuł:
A Note on the Thue Chromatic Number of Lexicographic Products of Graphs
Autorzy:
Peterin, Iztok
Schreyer, Jens
Škrabul’áková, Erika Fecková
Taranenko, Andrej
Powiązania:
https://bibliotekanauki.pl/articles/31342285.pdf
Data publikacji:
2018-08-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
non-repetitive colouring
Thue chromatic number
lexicographic product of graphs
Opis:
A sequence is called non-repetitive if none of its subsequences forms a repetition (a sequence r1r2⋯r2n such that ri = rn+i for all 1 ≤ i ≤ n). Let G be a graph whose vertices are coloured. A colouring ϕ of the graph G is non-repetitive if the sequence of colours on every path in G is non-repetitive. The Thue chromatic number, denoted by π(G), is the minimum number of colours of a non-repetitive colouring of G. In this short note we present two general upper bounds for the Thue chromatic number for the lexicographic product G ◦ H of graphs G and H with respect to some properties of the factors. One upper bound is then used to derive the exact values for π(G ◦ H) when G is a complete multipartite graph and H an arbitrary graph.
Źródło:
Discussiones Mathematicae Graph Theory; 2018, 38, 3; 635-643
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Closed Formulae for the Strong Metric Dimension of Lexicographic Product Graphs
Autorzy:
Kuziak, Dorota
Yero, Ismael G.
Rodríguez-Velázquez, Juan A.
Powiązania:
https://bibliotekanauki.pl/articles/31340465.pdf
Data publikacji:
2016-11-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
strong metric dimension
strong metric basis
strong metric generator
lexicographic product graphs
Opis:
Given a connected graph G, a vertex w ∈ V (G) strongly resolves two vertices u, v ∈ V (G) if there exists some shortest u − w path containing v or some shortest v − w path containing u. A set S of vertices is a strong metric generator for G if every pair of vertices of G is strongly resolved by some vertex of S. The smallest cardinality of a strong metric generator for G is called the strong metric dimension of G. In this paper we obtain several relationships between the strong metric dimension of the lexicographic product of graphs and the strong metric dimension of its factor graphs.
Źródło:
Discussiones Mathematicae Graph Theory; 2016, 36, 4; 1051-1064
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Edge-Transitive Lexicographic and Cartesian Products
Autorzy:
Imrich, Wilfried
Iranmanesh, Ali
Klavžar, Sandi
Soltani, Abolghasem
Powiązania:
https://bibliotekanauki.pl/articles/31340755.pdf
Data publikacji:
2016-11-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
edge-transitive graph
vertex-transitive graph
lexicographic product of graphs
Cartesian product of graphs
Opis:
In this note connected, edge-transitive lexicographic and Cartesian products are characterized. For the lexicographic product G ◦ H of a connected graph G that is not complete by a graph H, we show that it is edge-transitive if and only if G is edge-transitive and H is edgeless. If the first factor of G ∘ H is non-trivial and complete, then G ∘ H is edge-transitive if and only if H is the lexicographic product of a complete graph by an edgeless graph. This fixes an error of Li, Wang, Xu, and Zhao [11]. For the Cartesian product it is shown that every connected Cartesian product of at least two non-trivial factors is edge-transitive if and only if it is the Cartesian power of a connected, edge- and vertex-transitive graph.
Źródło:
Discussiones Mathematicae Graph Theory; 2016, 36, 4; 857-865
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Minimal cycle bases of the lexicographic product of graphs
Autorzy:
Jaradat, M.
Powiązania:
https://bibliotekanauki.pl/articles/743317.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
cycle space
lexicographic product
cycle basis
Opis:
A construction of minimum cycle bases of the lexicographic product of graphs is presented. Moreover, the length of a longest cycle of a minimal cycle basis is determined.
Źródło:
Discussiones Mathematicae Graph Theory; 2008, 28, 2; 229-247
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-1-Planarity of Lexicographic Products of Graphs
Autorzy:
Matsumoto, Naoki
Suzuki, Yusuke
Powiązania:
https://bibliotekanauki.pl/articles/32222720.pdf
Data publikacji:
2021-11-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
1-planar graph
lexicographic product
Opis:
In this paper, we show the non-1-planarity of the lexicographic product of a theta graph and K2. This result completes the proof of the conjecture that a graph G ◦ K2 is 1-planar if and only if G has no edge belonging to two cycles.
Źródło:
Discussiones Mathematicae Graph Theory; 2021, 41, 4; 1103-1114
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Protection of Lexicographic Product Graphs
Autorzy:
Klein, Douglas J.
Rodríguez-Velázquez, Juan A.
Powiązania:
https://bibliotekanauki.pl/articles/32361746.pdf
Data publikacji:
2022-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
lexicographic product
weak Roman domination
secure domination
total domination
double total domination
Opis:
In this paper, we study the weak Roman domination number and the secure domination number of lexicographic product graphs. In particular, we show that these two parameters coincide for almost all lexicographic product graphs. Furthermore, we obtain tight bounds and closed formulas for these parameters.
Źródło:
Discussiones Mathematicae Graph Theory; 2022, 42, 1; 139-158
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sharp Upper Bounds for Generalized Edge-Connectivity of Product Graphs
Autorzy:
Sun, Yuefang
Powiązania:
https://bibliotekanauki.pl/articles/31340760.pdf
Data publikacji:
2016-11-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
generalized edge-connectivity
Cartesian product
strong product
lexicographic product
Opis:
The generalized $k$-connectivity $ \kappa_k (G) $ of a graph $G$ was introduced by Hager in 1985. As a natural counterpart of this concept, Li et al. in 2011 introduced the concept of generalized $k$-edge-connectivity which is defined as $ \lambda k(G) = \text{min} \{ \lambda (S) : S \subseteq V (G) \text{ and } |S| = k \} $, where $ \lambda(S) $ denote the maximum number $ \mathcal{l} $ of pairwise edge-disjoint trees $ T_1, T_2, . . ., T_\mathcal{l} $ in $G$ such that $ S \subseteq V ( T_i ) $ for $ 1 \le i \le \mathcal{l} $. In this paper, we study the generalized edge- connectivity of product graphs and obtain sharp upper bounds for the generalized 3-edge-connectivity of Cartesian product graphs and strong product graphs. Among our results, some special cases are also discussed.
Źródło:
Discussiones Mathematicae Graph Theory; 2016, 36, 4; 833-843
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Vertex-Rainbow Connection Number of Some Graph Operations
Autorzy:
Li, Hengzhe
Ma, Yingbin
Li, Xueliang
Powiązania:
https://bibliotekanauki.pl/articles/32083892.pdf
Data publikacji:
2021-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
rainbow connection number
vertex-rainbow connection number
Cartesian product
lexicographic product
line graph
Opis:
A path in an edge-colored (respectively vertex-colored) graph G is rainbow (respectively vertex-rainbow) if no two edges (respectively internal vertices) of the path are colored the same. An edge-colored (respectively vertex-colored) graph G is rainbow connected (respectively vertex-rainbow connected) if every two distinct vertices are connected by a rainbow (respectively vertex-rainbow) path. The rainbow connection number rc(G) (respectively vertex-rainbow connection number rvc(G)) of G is the smallest number of colors that are needed in order to make G rainbow connected (respectively vertex-rainbow connected). In this paper, we show that for a connected graph G and any edge e = xy ∈ E(G), rvc(G) ≤ rvc(G − e) ≤ rvc(G) + dG−e(x, y) − 1 if G − e is connected. For any two connected, non-trivial graphs G and H, rad(G□H)−1 ≤ rvc(G□H) ≤ 2rad(G□H), where G□H is the Cartesian product of G and H. For any two non-trivial graphs G and H such that G is connected, rvc(G ◦ H) = 1 if diam(G ◦ H) ≤ 2, rad(G) − 1 ≤ rvc(G ◦ H) ≤ 2rad(G) if diam(G) > 2, where G ◦ H is the lexicographic product of G and H. For the line graph L(G) of a graph G we show that rvc(L(G)) ≤ rc(G), which is the first known nontrivial inequality between the rainbow connection number and vertex-rainbow connection number. Moreover, the bounds reported are tight or tight up to additive constants.
Źródło:
Discussiones Mathematicae Graph Theory; 2021, 41, 2; 513-530
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Total Protection of Lexicographic Product Graphs
Autorzy:
Martínez, Abel Cabrera
Rodríguez-Velázquez, Juan Alberto
Powiązania:
https://bibliotekanauki.pl/articles/32304140.pdf
Data publikacji:
2022-08-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
total weak Roman domination
secure total domination
total domination
lexicographic product
Opis:
Given a graph G with vertex set V (G), a function f : V (G) → {0, 1, 2} is said to be a total dominating function if Σu∈N(v) f(u) > 0 for every v ∈ V (G), where N(v) denotes the open neighbourhood of v. Let Vi = {x ∈ V (G) : f(x) = i}. A total dominating function f is a total weak Roman dominating function if for every vertex v ∈ V0 there exists a vertex u ∈ N(v) ∩ (V1 ∪ V2) such that the function f′, defined by f′(v) = 1, f′(u) = f(u) − 1 and f′(x) = f(x) whenever x ∈ V (G) \ {u, v}, is a total dominating function as well. If f is a total weak Roman dominating function and V2 = ∅, then we say that f is a secure total dominating function. The weight of a function f is defined to be ω(f) = Σv∈V (G) f(v). The total weak Roman domination number (secure total domination number) of a graph G is the minimum weight among all total weak Roman dominating functions (secure total dominating functions) on G. In this article, we show that these two parameters coincide for lexicographic product graphs. Furthermore, we obtain closed formulae and tight bounds for these parameters in terms of invariants of the factor graphs involved in the product.
Źródło:
Discussiones Mathematicae Graph Theory; 2022, 42, 3; 967-984
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Union of Distance Magic Graphs
Autorzy:
Cichacz, Sylwia
Nikodem, Mateusz
Powiązania:
https://bibliotekanauki.pl/articles/31342130.pdf
Data publikacji:
2017-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
distance magic labeling
magic constant
sigma labeling
graph labeling
union of graphs
lexicographic product
direct product
Kronecker product
Kotzig array
Opis:
A distance magic labeling of a graph $G = (V,E)$ with $|V | = n$ is a bijection $ \mathcal{l} $ from $V$ to the set ${1, . . ., n}$ such that the weight $ w(x) = \Sigma_{ y \in N_G } (x) \mathcal{l}(y) $ of every vertex $ x \in V $ is equal to the same element $ \mu $, called the magic constant. In this paper, we study unions of distance magic graphs as well as some properties of such graphs.
Źródło:
Discussiones Mathematicae Graph Theory; 2017, 37, 1; 239-249
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-10 z 10

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