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Wyszukujesz frazę "Hedetniemi, Stephen T." wg kryterium: Autor


Wyświetlanie 1-3 z 3
Tytuł:
Downhill domination in graphs
Autorzy:
Haynes, Teresa W.
Hedetniemi, Stephen T.
Jamieson, Jessie D.
Jamieson, William B.
Powiązania:
https://bibliotekanauki.pl/articles/30148687.pdf
Data publikacji:
2014-08-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
downhill path
downhill domination number
Opis:
A path $π = (v_1, v_2, . . ., v_{k+1})$ in a graph $G = (V,E)$ is a downhill path if for every $i, 1 ≤ i ≤ k, deg(v_i) ≥ deg(v_{i+1})$, where $deg(v_i)$ denotes the degree of vertex $v_i ∈ V$. The downhill domination number equals the minimum cardinality of a set $S ⊆ V$ having the property that every vertex $v ∈ V$ lies on a downhill path originating from some vertex in $S$. We investigate downhill domination numbers of graphs and give upper bounds. In particular, we show that the downhill domination number of a graph is at most half its order, and that the downhill domination number of a tree is at most one third its order. We characterize the graphs obtaining each of these bounds.
Źródło:
Discussiones Mathematicae Graph Theory; 2014, 34, 3; 603-612
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rainbow Disconnection in Graphs
Autorzy:
Chartrand, Gary
Devereaux, Stephen
Haynes, Teresa W.
Hedetniemi, Stephen T.
Zhang, Ping
Powiązania:
https://bibliotekanauki.pl/articles/31342243.pdf
Data publikacji:
2018-11-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
edge coloring
rainbow connection
rainbow disconnection
Opis:
Let G be a nontrivial connected, edge-colored graph. An edge-cut R of G is called a rainbow cut if no two edges in R are colored the same. An edge-coloring of G is a rainbow disconnection coloring if for every two distinct vertices u and v of G, there exists a rainbow cut in G, where u and v belong to different components of G − R. We introduce and study the rainbow disconnection number rd(G) of G, which is defined as the minimum number of colors required of a rainbow disconnection coloring of G. It is shown that the rainbow disconnection number of a nontrivial connected graph G equals the maximum rainbow disconnection number among the blocks of G. It is also shown that for a nontrivial connected graph G of order n, rd(G) = n−1 if and only if G contains at least two vertices of degree n − 1. The rainbow disconnection numbers of all grids Pm □ Pn are determined. Furthermore, it is shown for integers k and n with 1 ≤ k ≤ n − 1 that the minimum size of a connected graph of order n having rainbow disconnection number k is n + k − 2. Other results and a conjecture are also presented.
Źródło:
Discussiones Mathematicae Graph Theory; 2018, 38, 4; 1007-1021
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Self-coalition graphs
Autorzy:
Haynes, Teresa W.
Hedetniemi, Jason T.
Hedetniemi, Stephen T.
McRae, Alice A.
Mohan, Raghuveer
Powiązania:
https://bibliotekanauki.pl/articles/29519279.pdf
Data publikacji:
2023
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
coalitions in graphs
coalition partitions
coalition graphs
domination
Opis:
A coalition in a graph $ G = (V,E) $ consists of two disjoint sets $ V_1 $ and $ V_2 $ of vertices, such that neither $ V_1 $ nor $ V_2 $ is a dominating set, but the union $ V_1 ∪ V_2 $ is a dominating set of $ G $. A coalition partition in a graph $ G $ of order $ n = |V| $ is a vertex partition $ π = {V_1, V_2, . . . , V_k} $ such that every set $ V_i $ either is a dominating set consisting of a single vertex of degree $ n − 1 $, or is not a dominating set but forms a coalition with another set $ V_j $ which is not a dominating set. Associated with every coalition partition $ π $ of a graph $ G $ is a graph called the coalition graph of $ G $ with respect to $ π $, denoted $ CG(G, π) $, the vertices of which correspond one-to-one with the sets $ V_1, V_2, . . . , V_k $ of $ π $ and two vertices are adjacent in $ CG(G, π) $ if and only if their corresponding sets in $ π $ form a coalition. The singleton partition $ π_1 $ of the vertex set of $ G $ is a partition of order $ |V| $, that is, each vertex of $ G $ is in a singleton set of the partition. A graph $ G $ is called a self-coalition graph if $ G $ is isomorphic to its coalition graph $ CG(G, π_1)$, where $π_1$ is the singleton partition of $ G $. In this paper, we characterize self-coalition graphs.
Źródło:
Opuscula Mathematica; 2023, 43, 2; 173-183
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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