Quasi-total Roman bondage number in graphs

AbstractA quasi-total Roman dominating function (QTRD-function) on [Formula: see text] is a function [Formula: see text] such that (i) every vertex x for which f(x) = 0 is adjacent to at least one vertex v for which f(v) = 2, and (ii) if x is an isolated vertex in the subgraph induced by the set of...

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Main Authors: Huiqin Jiang, Zehui Shao
Format: Article
Language:English
Published: Taylor & Francis Group 2022-09-01
Series:AKCE International Journal of Graphs and Combinatorics
Subjects:
Online Access:https://www.tandfonline.com/doi/10.1080/09728600.2022.2098876
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author Huiqin Jiang
Zehui Shao
author_facet Huiqin Jiang
Zehui Shao
author_sort Huiqin Jiang
collection DOAJ
description AbstractA quasi-total Roman dominating function (QTRD-function) on [Formula: see text] is a function [Formula: see text] such that (i) every vertex x for which f(x) = 0 is adjacent to at least one vertex v for which f(v) = 2, and (ii) if x is an isolated vertex in the subgraph induced by the set of vertices with non-zero values, then f(x) = 1. The weight of a QTRD-function is the sum of its function values over the whole set of vertices, and the quasi-total Roman domination number is the minimum weight of a QTRD-function on G. The quasi-total Roman bondage number [Formula: see text] of a graph G is the minimum number of edges that have to be deleted to G in order to increase the quasi-total Roman domination number. In this paper, we start the study of quasi-total Roman bondage in graphs. We first show that the decision problem associated with the quasi-total Roman bondage problem is NP-hard even when restricted to bipartite graphs. Then basic properties of the quasi-total Roman bondage number are provided. Finally, some sharp bounds for [Formula: see text] are also presented.
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spelling doaj.art-e2fd17de9b194b4899d364ebb94135072022-12-22T02:48:47ZengTaylor & Francis GroupAKCE International Journal of Graphs and Combinatorics0972-86002543-34742022-09-0119322122810.1080/09728600.2022.2098876Quasi-total Roman bondage number in graphsHuiqin Jiang0Zehui Shao1Institute of Computing Science and Technology, Guangzhou University, Guangzhou, ChinaInstitute of Computing Science and Technology, Guangzhou University, Guangzhou, ChinaAbstractA quasi-total Roman dominating function (QTRD-function) on [Formula: see text] is a function [Formula: see text] such that (i) every vertex x for which f(x) = 0 is adjacent to at least one vertex v for which f(v) = 2, and (ii) if x is an isolated vertex in the subgraph induced by the set of vertices with non-zero values, then f(x) = 1. The weight of a QTRD-function is the sum of its function values over the whole set of vertices, and the quasi-total Roman domination number is the minimum weight of a QTRD-function on G. The quasi-total Roman bondage number [Formula: see text] of a graph G is the minimum number of edges that have to be deleted to G in order to increase the quasi-total Roman domination number. In this paper, we start the study of quasi-total Roman bondage in graphs. We first show that the decision problem associated with the quasi-total Roman bondage problem is NP-hard even when restricted to bipartite graphs. Then basic properties of the quasi-total Roman bondage number are provided. Finally, some sharp bounds for [Formula: see text] are also presented.https://www.tandfonline.com/doi/10.1080/09728600.2022.2098876Quasi-total Roman domination numberquasi-total Roman bondage numbercomplexity05C0505C69
spellingShingle Huiqin Jiang
Zehui Shao
Quasi-total Roman bondage number in graphs
AKCE International Journal of Graphs and Combinatorics
Quasi-total Roman domination number
quasi-total Roman bondage number
complexity
05C05
05C69
title Quasi-total Roman bondage number in graphs
title_full Quasi-total Roman bondage number in graphs
title_fullStr Quasi-total Roman bondage number in graphs
title_full_unstemmed Quasi-total Roman bondage number in graphs
title_short Quasi-total Roman bondage number in graphs
title_sort quasi total roman bondage number in graphs
topic Quasi-total Roman domination number
quasi-total Roman bondage number
complexity
05C05
05C69
url https://www.tandfonline.com/doi/10.1080/09728600.2022.2098876
work_keys_str_mv AT huiqinjiang quasitotalromanbondagenumberingraphs
AT zehuishao quasitotalromanbondagenumberingraphs