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Wyświetlanie 1-10 z 10
Tytuł:
The irregularity of graphs under graph operations
Autorzy:
Abdo, Hosam
Dimitrov, Darko
Powiązania:
https://bibliotekanauki.pl/articles/30148232.pdf
Data publikacji:
2014-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
irregularity of graphs
total irregularity of graphs
graph operations
Zagreb indices
Opis:
The irregularity of a simple undirected graph $G$ was defined by Albertson [5] as $irr(G) = ∑_{uv∈E(G)} |dG(u) − dG(v)|$, where $d_G(u)$ denotes the degree of a vertex $u ∈ V (G)$. In this paper we consider the irregularity of graphs under several graph operations including join, Cartesian product, direct product, strong product, corona product, lexicographic product, disjunction and symmetric difference. We give exact expressions or (sharp) upper bounds on the irregularity of graphs under the above mentioned operations
Źródło:
Discussiones Mathematicae Graph Theory; 2014, 34, 2; 263-278
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On H-Irregularity Strength Of Graphs
Autorzy:
Ashraf, Faraha
Bača, Martin
Lascśaková, Marcela
Semaničová-Feňovčíková, Andrea
Powiązania:
https://bibliotekanauki.pl/articles/31341574.pdf
Data publikacji:
2017-11-27
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
H-covering
H-irregular labeling
H-irregularity strength
Opis:
New graph characteristic, the total H-irregularity strength of a graph, is introduced. Estimations on this parameter are obtained and for some families of graphs the precise values of this parameter are proved.
Źródło:
Discussiones Mathematicae Graph Theory; 2017, 37, 4; 1067-1078
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On total vertex irregularity strength of graphs
Autorzy:
Muthu Guru Packiam, K.
Kathiresan, Kumarappan
Powiązania:
https://bibliotekanauki.pl/articles/743655.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
graph labeling
irregularity strength
total assignment
vertex irregular total labeling
Opis:
Martin Bača et al. [2] introduced the problem of determining the total vertex irregularity strengths of graphs. In this paper we discuss how the addition of new edge affect the total vertex irregularity strength.
Źródło:
Discussiones Mathematicae Graph Theory; 2012, 32, 1; 39-45
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Distance irregularity strength of graphs with pendant vertices
Autorzy:
Susanto, Faisal
Wijaya, Kristiana
Slamin
Semaničová-Feňovčíková, Andrea
Powiązania:
https://bibliotekanauki.pl/articles/2216177.pdf
Data publikacji:
2022
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
vertex k-labeling
distance irregular vertex k-labeling
distance irregularity strength
pendant vertices
Opis:
A vertex k-labeling ϕ : V (G) → {1, 2, . . . , k} on a simple graph G is said to be a distance irregular vertex k-labeling of G if the weights of all vertices of G are pairwise distinct, where the weight of a vertex is the sum of labels of all vertices adjacent to that vertex in G. The least integer k for which G has a distance irregular vertex k-labeling is called the distance irregularity strength of G and denoted by dis(G). In this paper, we introduce a new lower bound of distance irregularity strength of graphs and provide its sharpness for some graphs with pendant vertices. Moreover, some properties on distance irregularity strength for trees are also discussed in this paper.
Źródło:
Opuscula Mathematica; 2022, 42, 3; 439-458
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Edge H-Irregularity Strengths of Some Graphs
Autorzy:
Naeem, Muhammad
Siddiqui, Muhammad Kamran
Bača, Martin
Semaničová-Feňovčíková, Andrea
Ashraf, Faraha
Powiązania:
https://bibliotekanauki.pl/articles/32225869.pdf
Data publikacji:
2021-11-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
prism
antiprism
triangular ladder
diagonal ladder
wheel
gear graph
H-irregular edge labeling
edge H-irregularity strength
Opis:
For a graph G an edge-covering of G is a family of subgraphs H1, H2, . . ., Ht such that each edge of E(G) belongs to at least one of the subgraphs Hi, i = 1, 2, . . ., t. In this case we say that G admits an (H1, H2, . . ., Ht)-(edge) covering. An H-covering of graph G is an (H1, H2, . . ., Ht)-(edge) covering in which every subgraph Hi is isomorphic to a given graph H. Let G be a graph admitting H-covering. An edge k-labeling α : E(G) → {1, 2, . . ., k} is called an H-irregular edge k-labeling of the graph G if for every two different subgraphs H′ and H′′ isomorphic to H their weights wtα(H′) and wtα(H′″) are distinct. The weight of a subgraph H under an edge k-labeling is the sum of labels of edges belonging to H. The edge H-irregularity strength of a graph G, denoted by ehs(G, H), is the smallest integer k such that G has an H-irregular edge k-labeling. In this paper we determine the exact values of ehs(G, H) for prisms, antiprisms, triangular ladders, diagonal ladders, wheels and gear graphs. Moreover the subgraph H is isomorphic to only C4, C3 and K4.
Źródło:
Discussiones Mathematicae Graph Theory; 2021, 41, 4; 949-961
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Upper bounds on distance vertex irregularity strength of some families of graphs
Autorzy:
Cichacz, Sylwia
Görlich, Agnieszka
Semaničová-Feňovčíková, Andrea
Powiązania:
https://bibliotekanauki.pl/articles/2216229.pdf
Data publikacji:
2022
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
distance vertex irregularity strength of a graph
hypercube
tree
graph
Opis:
For a graph G its distance vertex irregularity strength is the smallest integer k for which one can find a labeling f : V (G) → {1, 2, . . . , k} such that $ \sum_{x \in N(v)} f(x) \neq \sum_{x \in N(u)} f(x) $ for all vertices u, v of G, where N(v) is the open neighborhood of v. In this paper we present some upper bounds on distance vertex irregularity strength of general graphs. Moreover, we give upper bounds on distance vertex irregularity strength of hypercubes and trees.
Źródło:
Opuscula Mathematica; 2022, 42, 4; 561--571
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Total vertex irregularity strength of disjoint union of Helm graphs
Autorzy:
Ahmad, Ali
Baskoro, E.
Imran, M.
Powiązania:
https://bibliotekanauki.pl/articles/743230.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
vertex irregular total k-labeling
Helm graphs
total vertex irregularity strength
Opis:
A total vertex irregular k-labeling φ of a graph G is a labeling of the vertices and edges of G with labels from the set {1,2,...,k} in such a way that for any two different vertices x and y their weights wt(x) and wt(y) are distinct. Here, the weight of a vertex x in G is the sum of the label of x and the labels of all edges incident with the vertex x. The minimum k for which the graph G has a vertex irregular total k-labeling is called the total vertex irregularity strength of G. We have determined an exact value of the total vertex irregularity strength of disjoint union of Helm graphs.
Źródło:
Discussiones Mathematicae Graph Theory; 2012, 32, 3; 427-434
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Total H-Irregularity Strength of the Disjoint Union of Graphs
Autorzy:
Ashraf, Faraha
López, Susana Clara
Muntaner-Batle, Francesc Antoni
Oshima, Akito
Bača, Martin
Semaničová-Feňovčíková, Andrea
Powiązania:
https://bibliotekanauki.pl/articles/32083832.pdf
Data publikacji:
2020-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
H -covering
H -irregular labeling
total H -irregularity strength
copies of graphs
union of graphs
Opis:
A simple graph G admits an H-covering if every edge in E(G) belongs to at least to one subgraph of G isomorphic to a given graph H. For the subgraph H ⊆ G under a total k-labeling we define the associated H-weight as the sum of labels of all vertices and edges belonging to H. The total k-labeling is called the H-irregular total k-labeling of a graph G admitting an H-covering if all subgraphs of G isomorphic to H have distinct weights. The total H-irregularity strength of a graph G is the smallest integer k such that G has an H-irregular total k-labeling. In this paper, we estimate lower and upper bounds on the total H-irregularity strength for the disjoint union of multiple copies of a graph and the disjoint union of two non-isomorphic graphs. We also prove the sharpness of the upper bounds.
Źródło:
Discussiones Mathematicae Graph Theory; 2020, 40, 1; 181-194
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Face Irregular Evaluations of Plane Graphs
Autorzy:
Bača, Martin
Ovais, Ali
Semaničová-Feňovčíková, Andrea
Suparta, I. Nengah
Powiązania:
https://bibliotekanauki.pl/articles/32319469.pdf
Data publikacji:
2022-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
plane graphs
irregular assignment
irregularity strength
face irregular labeling
face irregularity strength
Opis:
We investigate face irregular labelings of plane graphs and we introduce new graph characteristics, namely face irregularity strength of type (α,β,γ). We obtain some estimation on these parameters and determine the precise values for certain families of plane graphs that prove the sharpness of the lower bounds.
Źródło:
Discussiones Mathematicae Graph Theory; 2022, 42, 2; 549-568
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New results on imbalance graphic graphs
Autorzy:
Kozerenko, Sergiy
Serdiuk, Andrii
Powiązania:
https://bibliotekanauki.pl/articles/29519186.pdf
Data publikacji:
2023
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
edge imbalance
irregularity of a graph
imbalance sequence
graphic sequence
Opis:
An edge imbalance provides a local measure of how irregular a given graph is. In this paper, we study graphs with graphic imbalance sequences. We give a new proof of imbalance graphicness for trees and use the new idea to prove that the same holds for unicyclic graphs. We then show that antiregular graphs are imbalance graphic and consider the join operation on graphs as well as the double graph operation. Our main results are concerning imbalance graphicness of three classes of block graphs: block graphs having all cut vertices in a single block; block graphs in which the subgraph induced by the cut vertices is either a star or a path. In the end, we discuss open questions and conjectures regarding imbalance graphic graphs.
Źródło:
Opuscula Mathematica; 2023, 43, 1; 81-100
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-10 z 10

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