Twin signed domination numbers in directed graphs
Let D=(V,A) be a finite simple directed graph (shortly digraph). A function f:V⟶{−1,1} is called a twin signed dominating function (TSDF) if f(N⁻[v])≥1 and f(N⁺[v])≥1 for each vertex v∈V. The twin signed domination number of D is γs*(D)=min{ω(f)∣f is a TSDF of D}. In this paper, we initiate the stud...
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| Datum: | 2017 |
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| Hauptverfasser: | , , , |
| Format: | Artikel |
| Sprache: | English |
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Інститут прикладної математики і механіки НАН України
2017
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| Schriftenreihe: | Algebra and Discrete Mathematics |
| Online Zugang: | http://dspace.nbuv.gov.ua/handle/123456789/156254 |
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| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Zitieren: | Twin signed domination numbers in directed graphs / M. Atapour, S. Norouzian, S.M. Sheikholeslami, L. Volkmann // Algebra and Discrete Mathematics. — 2017. — Vol. 24, № 1. — С. 71-89. — Бібліогр.: 10 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| Zusammenfassung: | Let D=(V,A) be a finite simple directed graph (shortly digraph). A function f:V⟶{−1,1} is called a twin signed dominating function (TSDF) if f(N⁻[v])≥1 and f(N⁺[v])≥1 for each vertex v∈V. The twin signed domination number of D is γs*(D)=min{ω(f)∣f is a TSDF of D}. In this paper, we initiate the study of twin signed domination in digraphs and we present sharp lower bounds for γs*(D) in terms of the order, size and maximum and minimum indegrees and outdegrees. Some of our results are extensions of well-known lower bounds of the classical signed domination numbers of graphs. |
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