Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "total domination" wg kryterium: Temat


Tytuł:
3-Tuple Total Domination Number of Rook’s Graphs
Autorzy:
Pahlavsay, Behnaz
Palezzato, Elisa
Torielli, Michele
Powiązania:
https://bibliotekanauki.pl/articles/32361755.pdf
Data publikacji:
2022-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
k -tuple total domination
Cartesian product of graphs
rook’s graph
Vizing’s conjecture
Opis:
A k-tuple total dominating set (kTDS) of a graph G is a set S of vertices in which every vertex in G is adjacent to at least k vertices in S. The minimum size of a kTDS is called the k-tuple total dominating number and it is denoted by γ×k,t(G). We give a constructive proof of a general formula for γ×3,t(Kn□Km).
Źródło:
Discussiones Mathematicae Graph Theory; 2022, 42, 1; 15-37
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Further Results on Packing Related Parameters in Graphs
Autorzy:
Mojdeh, Doost Ali
Samadi, Babak
Yero, Ismael G.
Powiązania:
https://bibliotekanauki.pl/articles/32361731.pdf
Data publikacji:
2022-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
packing number
open packing number
independence number
Nordhaus-Gaddum inequality
total domination number
Opis:
Given a graph G = (V, E), a set B ⊆ V (G) is a packing in G if the closed neighborhoods of every pair of distinct vertices in B are pairwise disjoint. The packing number ρ(G) of G is the maximum cardinality of a packing in G. Similarly, open packing sets and open packing number are defined for a graph G by using open neighborhoods instead of closed ones. We give several results concerning the (open) packing number of graphs in this paper. For instance, several bounds on these packing parameters along with some Nordhaus-Gaddum inequalities are given. We characterize all graphs with equal packing and independence numbers and give the characterization of all graphs for which the packing number is equal to the independence number minus one. In addition, due to the close connection between the open packing and total domination numbers, we prove a new upper bound on the total domination number γt(T) for a tree T of order n ≥ 2 improving the upper bound γt(T) ≤ (n + s)/2 given by Chellali and Haynes in 2004, in which s is the number of support vertices of T.
Źródło:
Discussiones Mathematicae Graph Theory; 2022, 42, 2; 333-348
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nordhaus-Gaddum bounds for upper total domination
Autorzy:
Haynes, Teresa W.
Henning, Michael A.
Powiązania:
https://bibliotekanauki.pl/articles/2216175.pdf
Data publikacji:
2022
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
upper total domination
Nordhaus-Gaddum bound
Opis:
A set S of vertices in an isolate-free graph G is a total dominating set if every vertex in G is adjacent to a vertex in S. A total dominating set of G is minimal if it contains no total dominating set of $\bar{G}$ as a proper subset. The upper total domination number $Γ_t(G)$ of G is the maximum cardinality of a minimal total dominating set in G. We establish Nordhaus-Gaddum bounds involving the upper total domination numbers of a graph G and its complement $\bar{G}$. We prove that if G is a graph of order n such that both G and $\bar{G}$ are isolate-free, then $Γ_t(G) + Γ_t(\bar{G}) ≤ n + 2$ and $Γ_t(G)Γ_t(\bar{G}) ≤ 1/4 (n + 2)^2$, and these bounds are tight.
Źródło:
Opuscula Mathematica; 2022, 42, 4; 573-582
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
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:
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:
Total Roman {2}-Dominating Functions in Graphs
Autorzy:
Ahangar, H. Abdollahzadeh
Chellali, M.
Sheikholeslami, S.M.
Valenzuela-Tripodoro, J.C.
Powiązania:
https://bibliotekanauki.pl/articles/32304142.pdf
Data publikacji:
2022-08-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
Roman domination
Roman {2}-domination
total Roman {2}-domination
Opis:
A Roman {2}-dominating function (R2F) is a function f : V → {0, 1, 2} with the property that for every vertex v ∈ V with f(v) = 0 there is a neighbor u of v with f(u) = 2, or there are two neighbors x, y of v with f(x) = f(y) = 1. A total Roman {2}-dominating function (TR2DF) is an R2F f such that the set of vertices with f(v) > 0 induce a subgraph with no isolated vertices. The weight of a TR2DF is the sum of its function values over all vertices, and the minimum weight of a TR2DF of G is the total Roman {2}-domination number γtR2(G). In this paper, we initiate the study of total Roman {2}-dominating functions, where properties are established. Moreover, we present various bounds on the total Roman {2}-domination number. We also show that the decision problem associated with γtR2(G) is possible to compute this parameter in linear time for bounded clique-width graphs (including trees).
Źródło:
Discussiones Mathematicae Graph Theory; 2022, 42, 3; 937-958
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A New Framework to Approach Vizing’s Conjecture
Autorzy:
Brešar, Boštjan
Hartnell, Bert L.
Henning, Michael A.
Kuenzel, Kirsti
Rall, Douglas F.
Powiązania:
https://bibliotekanauki.pl/articles/32222699.pdf
Data publikacji:
2021-08-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
Cartesian product
total domination
Vizing’s conjecture
Clark and Suen bound
Opis:
We introduce a new setting for dealing with the problem of the domination number of the Cartesian product of graphs related to Vizing’s conjecture. The new framework unifies two different approaches to the conjecture. The most common approach restricts one of the factors of the product to some class of graphs and proves the inequality of the conjecture then holds when the other factor is any graph. The other approach utilizes the so-called Clark-Suen partition for proving a weaker inequality that holds for all pairs of graphs. We demonstrate the strength of our framework by improving the bound of Clark and Suen as follows: $ \gamma (X \square Y) \ge \max \{\frac{1}{2} \gamma (X) \gamma_t (Y), \frac{1}{2} \gamma_t (X) \gamma (Y) \} $, where $ \gamma $ stands for the domination number, $ \gamma_t $ is the total domination number, and $ X \square Y $ is the Cartesian product of graphs $X$ and $Y$.
Źródło:
Discussiones Mathematicae Graph Theory; 2021, 41, 3; 749-762
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fair Total Domination Number in Cactus Graphs
Autorzy:
Hajian, Majid
Rad, Nader Jafari
Powiązania:
https://bibliotekanauki.pl/articles/32083904.pdf
Data publikacji:
2021-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
fair total domination
cactus graph
Opis:
For k ≥ 1, a k-fair total dominating set (or just kFTD-set) in a graph G is a total dominating set S such that |N(v) ∩ S| = k for every vertex v ∈ V\S. The k-fair total domination number of G, denoted by ftdk(G), is the minimum cardinality of a kFTD-set. A fair total dominating set, abbreviated FTD-set, is a kFTD-set for some integer k ≥ 1. The fair total domination number of a nonempty graph G, denoted by ftd(G), of G is the minimum cardinality of an FTD-set in G. In this paper, we present upper bounds for the 1-fair total domination number of cactus graphs, and characterize cactus graphs achieving equality for the upper bounds.
Źródło:
Discussiones Mathematicae Graph Theory; 2021, 41, 2; 647-664
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Independent Transversal Total Domination versus Total Domination in Trees
Autorzy:
Martínez, Abel Cabrera
Peterin, Iztok
Yero, Ismael G.
Powiązania:
https://bibliotekanauki.pl/articles/32083825.pdf
Data publikacji:
2021-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
independent transversal total domination number
total domination number
independence number
trees
Opis:
A subset of vertices in a graph G is a total dominating set if every vertex in G is adjacent to at least one vertex in this subset. The total domination number of G is the minimum cardinality of any total dominating set in G and is denoted by γt(G). A total dominating set of G having nonempty intersection with all the independent sets of maximum cardinality in G is an independent transversal total dominating set. The minimum cardinality of any independent transversal total dominating set is denoted by γtt(G). Based on the fact that for any tree T, γt(T) ≤ γtt(T) ≤ γt(T) + 1, in this work we give several relationships between γtt(T) and γt(T) for trees T which are leading to classify the trees which are satisfying the equality in these bounds.
Źródło:
Discussiones Mathematicae Graph Theory; 2021, 41, 1; 213-224
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Grundy Total Domination Number in Product Graphs
Autorzy:
Brešar, Boštjan
Bujtás, Csilla
Gologranc, Tanja
Klavžar, Sandi
Košmrlj, Gašper
Marc, Tilen
Patkós, Balázs
Tuza, Zsolt
Vizer, Máté
Powiązania:
https://bibliotekanauki.pl/articles/32083828.pdf
Data publikacji:
2021-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
total domination
Grundy total domination number
graph product
Opis:
A longest sequence $(v_1, . . ., v_k)$ of vertices of a graph $G$ is a Grundy total dominating sequence of $G$ if for all $i$, \(N(υ_i)\backslash\bigcup_{j=1}^{i-1}N(υ_j)≠∅\). The length $k$ of the sequence is called the Grundy total domination number of $G$ and denoted $\gamma_{gr}^t(G)$. In this paper, the Grundy total domination number is studied on four standard graph products. For the direct product we show that $\gamma_{gr}^t(G×H)≥\gamma_{gr}^t(G)\gamma_{gr}^t(H)$, conjecture that the equality always holds, and prove the conjecture in several special cases. For the lexicographic product we express $\gamma_{gr}^t(G∘H)$ in terms of related invariant of the factors and find some explicit formulas for it. For the strong product, lower bounds on $\gamma_{gr}^t(G⊠H)$ are proved as well as upper bounds for products of paths and cycles. For the Cartesian product we prove lower and upper bounds on the Grundy total domination number when factors are paths or cycles.
Źródło:
Discussiones Mathematicae Graph Theory; 2021, 41, 1; 225-247
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Total 2-Rainbow Domination Numbers of Trees
Autorzy:
Ahangar, H. Abdollahzadeh
Amjadi, J.
Chellali, M.
Nazari-Moghaddam, S.
Sheikholeslami, S.M.
Powiązania:
https://bibliotekanauki.pl/articles/32083855.pdf
Data publikacji:
2021-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
2-rainbow dominating function
2-rainbow domination number
total 2-rainbow dominating function
total 2-rainbow domination number
Opis:
A 2-rainbow dominating function (2RDF) of a graph $G = (V(G), E(G))$ is a function $f$ from the vertex set $V(G)$ to the set of all subsets of the set {1, 2} such that for every vertex $v ∈ V(G)$ with $f(v) = ∅$ the condition \(\bigcup_{u∈N(v)}f(u) = \{1, 2\}\) is fulfilled, where $N(v)$ is the open neighborhood of $v$. A total 2-rainbow dominating function $f$ of a graph with no isolated vertices is a 2RDF with the additional condition that the subgraph of $G$ induced by $\{v ∈ V (G) | f(v) ≠∅\}$ has no isolated vertex. The total 2-rainbow domination number, $\gamma_{tr2}(G)$, is the minimum weight of a total 2-rainbow dominating function of $G$. In this paper, we establish some sharp upper and lower bounds on the total 2-rainbow domination number of a tree. Moreover, we show that the decision problem associated with $\gamma_{tr2}(G)$ is NP-complete for bipartite and chordal graphs.
Źródło:
Discussiones Mathematicae Graph Theory; 2021, 41, 2; 345-364
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Total connected domination game
Autorzy:
Bujtás, Csilla
Henning, Michael A.
Iršič, Vesna
Klavžar, Sandi
Powiązania:
https://bibliotekanauki.pl/articles/2050904.pdf
Data publikacji:
2021
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
connected domination game
total connected domination game
graph product
tree
Opis:
The (total) connected domination game on a graph $G$ is played by two players, Dominator and Staller, according to the standard (total) domination game with the additional requirement that at each stage of the game the selected vertices induce a connected subgraph of $G$. If Dominator starts the game and both players play optimally, then the number of vertices selected during the game is the (total) connected game domination number $(\gamma_{tcg}(G))(\gamma_{cg(G)})$ of $G$. We show that $\gamma_{tcg}(G) \in \{\gamma_{cg}(G), \gamma_{cg}(G)+1, \gamma_{cg}(G)+2\}$, and consequently define $G$ as Class $i$ if $\gamma_{tcg}(G) = \gamma_{cg}(G)+i$ for $i \in \{0, 1, 2\}$. A large family of Class 0 graphs is constructed which contains all connected Cartesian product graphs and connected direct product graphs with minimum degree at least 2. We show that no tree is Class 2 and characterize Class 1 trees. We provide an infinite family of Class 2 bipartite graphs.
Źródło:
Opuscula Mathematica; 2021, 41, 4; 453-464
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Total Domination in Generalized Prisms and a New Domination Invariant
Autorzy:
Tepeh, Aleksandra
Powiązania:
https://bibliotekanauki.pl/articles/32222717.pdf
Data publikacji:
2021-11-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
domination
k -rainbow total domination
total domination
Opis:
In this paper we complement recent studies on the total domination of prisms by considering generalized prisms, i.e., Cartesian products of an arbitrary graph and a complete graph. By introducing a new domination invariant on a graph G, called the k-rainbow total domination number and denoted by γkrt(G), it is shown that the problem of finding the total domination number of a generalized prism G □ Kk is equivalent to an optimization problem of assigning subsets of {1, 2, . . ., k} to vertices of G. Various properties of the new domination invariant are presented, including, inter alia, that γkrt(G) = n for a nontrivial graph G of order n as soon as k ≥ 2Δ(G). To prove the mentioned result as well as the closed formulas for the k-rainbow total domination number of paths and cycles for every k, a new weight-redistribution method is introduced, which serves as an efficient tool for establishing a lower bound for a domination invariant.
Źródło:
Discussiones Mathematicae Graph Theory; 2021, 41, 4; 1165-1178
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A note on bipartite graphs whose [1, k]-domination number equal to their number of vertices
Autorzy:
Ghareghani, Narges
Peterin, Iztok
Sharifani, Pouyeh
Powiązania:
https://bibliotekanauki.pl/articles/256007.pdf
Data publikacji:
2020
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
domination
[1, k]-domination number
[l,k]-total domination number
bipartite graphs
Opis:
A subset D of the vertex set V of a graph G is called an [1, k]-dominating set if every vertex from V — D is adjacent to at least one vertex and at most fc vertices of D. A [1, k]-dominating set with the minimum number of vertices is called a [formula]-set and the number of its vertices is the [1, k]-domination number [formula] of G. In this short note we show that the decision problem whether [formula] is an NP-hard problem, even for bipartite graphs. Also, a simple construction of a bipartite graph G of order n satisfying [formula] is given for every integer n ≥ (k + l)(2k + 3).
Źródło:
Opuscula Mathematica; 2020, 40, 3; 375-382
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bounds on the Locating-Total Domination Number in Trees
Autorzy:
Wang, Kun
Ning, Wenjie
Lu, Mei
Powiązania:
https://bibliotekanauki.pl/articles/31867549.pdf
Data publikacji:
2020-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
tree
total dominating set
locating-total dominating set
locating-total domination number
Opis:
Given a graph $G = (V, E)$ with no isolated vertex, a subset $S$ of $V$ is called a total dominating set of $G$ if every vertex in $V$ has a neighbor in $S$. A total dominating set $S$ is called a locating-total dominating set if for each pair of distinct vertices $u$ and $v$ in $V \ S, N(u) ∩ S ≠ N(v) ∩ S$. The minimum cardinality of a locating-total dominating set of $G$ is the locating-total domination number, denoted by $γ_t^L(G)$. We show that, for a tree $T$ of order $n ≥ 3$ and diameter $d$, \(\frac{d+1}{2}≤γ_t^L(T)≤n−\frac{d−1}{2}\), and if $T$ has $l$ leaves, $s$ support vertices and $s_1$ strong support vertices, then \(γ_t^L(T)≥max\Big\{\frac{n+l−s+1}{2}−\frac{s+s_1}{4},\frac{2(n+1)+3(l−s)−s_1}{5}\Big\}\). We also characterize the extremal trees achieving these bounds.
Źródło:
Discussiones Mathematicae Graph Theory; 2020, 40, 1; 25-34
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies