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Wyszukujesz frazę "Dettlaff, Magda" wg kryterium: Autor


Wyświetlanie 1-5 z 5
Tytuł:
Domination Subdivision and Domination Multisubdivision Numbers of Graphs
Autorzy:
Dettlaff, Magda
Raczek, Joanna
Topp, Jerzy
Powiązania:
https://bibliotekanauki.pl/articles/31343212.pdf
Data publikacji:
2019-11-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
domination
domination subdivision number
domination multisubdivision number
trees
computational complexity
Opis:
The domination subdivision number sd(G) of a graph G is the minimum number of edges that must be subdivided (where an edge can be subdivided at most once) in order to increase the domination number of G. It has been shown [10] that sd(T) ≤ 3 for any tree T. We prove that the decision problem of the domination subdivision number is NP-complete even for bipartite graphs. For this reason we define the domination multisubdivision number of a nonempty graph G as a minimum positive integer k such that there exists an edge which must be subdivided k times to increase the domination number of G. We show that msd(G) ≤ 3 for any graph G. The domination subdivision number and the domination multisubdivision number of a graph are incomparable in general, but we show that for trees these two parameters are equal. We also determine the domination multisubdivision number for some classes of graphs.
Źródło:
Discussiones Mathematicae Graph Theory; 2019, 39, 4; 829-839
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some Variations of Perfect Graphs
Autorzy:
Dettlaff, Magda
Lemańska, Magdalena
Semanišin, Gabriel
Zuazua, Rita
Powiązania:
https://bibliotekanauki.pl/articles/31340821.pdf
Data publikacji:
2016-08-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
k-path vertex cover
distance k-domination number
perfect graphs
Opis:
We consider (ψk−γk−1)-perfect graphs, i.e., graphs G for which ψk(H) = γk−1(H) for any induced subgraph H of G, where ψk and γk−1 are the k-path vertex cover number and the distance (k − 1)-domination number, respectively. We study (ψk−γk−1)-perfect paths, cycles and complete graphs for k ≥ 2. Moreover, we provide a complete characterisation of (ψ2 − γ1)- perfect graphs describing the set of its forbidden induced subgraphs and providing the explicit characterisation of the structure of graphs belonging to this family.
Źródło:
Discussiones Mathematicae Graph Theory; 2016, 36, 3; 661-668
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Total Domination Multisubdivision Number of a Graph
Autorzy:
Avella-Alaminos, Diana
Dettlaff, Magda
Lemańska, Magdalena
Zuazua, Rita
Powiązania:
https://bibliotekanauki.pl/articles/31339480.pdf
Data publikacji:
2015-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
(total) domination
(total) domination subdivision number
(total) domination multisubdivision number
trees
Opis:
The domination multisubdivision number of a nonempty graph G was defined in [3] as the minimum positive integer k such that there exists an edge which must be subdivided k times to increase the domination number of G. Similarly we define the total domination multisubdivision number msdγt (G) of a graph G and we show that for any connected graph G of order at least two, msdγt (G) ≤ 3. We show that for trees the total domination multisubdivision number is equal to the known total domination subdivision number. We also determine the total domination multisubdivision number for some classes of graphs and characterize trees T with msdγt (T) = 1.
Źródło:
Discussiones Mathematicae Graph Theory; 2015, 35, 2; 315-327
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Total Domination Versus Paired-Domination in Regular Graphs
Autorzy:
Cyman, Joanna
Dettlaff, Magda
Henning, Michael A.
Lemańska, Magdalena
Raczek, Joanna
Powiązania:
https://bibliotekanauki.pl/articles/31342314.pdf
Data publikacji:
2018-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
domination
total domination
paired-domination
Opis:
A subset S of vertices of a graph G is a dominating set of G if every vertex not in S has a neighbor in S, while S is a total dominating set of G if every vertex has a neighbor in S. If S is a dominating set with the additional property that the subgraph induced by S contains a perfect matching, then S is a paired-dominating set. The domination number, denoted γ(G), is the minimum cardinality of a dominating set of G, while the minimum cardinalities of a total dominating set and paired-dominating set are the total domination number, γt(G), and the paired-domination number, γpr(G), respectively. For k ≥ 2, let G be a connected k-regular graph. It is known [Schaudt, Total domination versus paired domination, Discuss. Math. Graph Theory 32 (2012) 435–447] that γpr(G)/γt(G) ≤ (2k)/(k+1). In the special case when k = 2, we observe that γpr(G)/γt(G) ≤ 4/3, with equality if and only if G ≅ C5. When k = 3, we show that γpr(G)/γt(G) ≤ 3/2, with equality if and only if G is the Petersen graph. More generally for k ≥ 2, if G has girth at least 5 and satisfies γpr(G)/γt(G) = (2k)/(k + 1), then we show that G is a diameter-2 Moore graph. As a consequence of this result, we prove that for k ≥ 2 and k ≠ 57, if G has girth at least 5, then γpr(G)/γt(G) ≤ (2k)/(k +1), with equality if and only if k = 2 and G ≅ C5 or k = 3 and G is the Petersen graph.
Źródło:
Discussiones Mathematicae Graph Theory; 2018, 38, 2; 573-586
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Graphs with equal domination and certified domination numbers
Autorzy:
Dettlaff, Magda
Lemańska, Magdalena
Miotk, Mateusz
Topp, Jerzy
Ziemann, Radosław
Żyliński, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/255932.pdf
Data publikacji:
2019
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
domination
certified domination
Opis:
A set D of vertices of a graph G = (VG, EG) is a dominating set of G if every vertex in VG — D is adjacent to at least one vertex in D. The domination number (upper domination number, respectively) of G, denoted by [formula], respectively), is the cardinality of a smallest (largest minimal, respectively) dominating set of G. A subset D ⊆ VG is called a certified dominating set of G if D is a dominating set of G and every vertex in D has either zero or at least two neighbors in VG — D. The cardinality of a smallest (largest minimal, respectively) certified dominating set of G is called the certified (upper certified, respectively) domination number of G and is denoted by [formula]), respectively). In this paper relations between domination, upper domination, certified domination and upper certified domination numbers of a graph are studied.
Źródło:
Opuscula Mathematica; 2019, 39, 6; 815-827
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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