Characterization of perfect Roman domination edge critical‎ ‎trees

  • Abdollah Alhevaz Faculty of Mathematical Sciences, Shahrood University of Technology, Iran
  • Mahsa Darkooti Faculty‎ of ‎Mathematical Sciences‎‎, ‎Shahrood University of ‎Technology, Iran
  • Sadegh Rahimi Faculty of Mathematical Sciences, Shahrood University of Technology, Iran
  • Hadi Rahbani Faculty‎ of ‎Mathematical Sciences‎‎, ‎Shahrood University of ‎Technology, Iran

Abstract

‎A perfect Roman dominating function on a graph $G =(V‎, ‎E)$ is a function $f‎: ‎V \longrightarrow \{0‎, ‎1‎, ‎2\}$‎

‎satisfying the condition that every vertex $u$ with $f(u) = 0$ is adjacent to exactly one vertex‎

‎$v$ for which $f(v) = 2$‎. ‎The weight of a perfect Roman dominating function $f$ is the sum of‎

‎the weights of the vertices‎. ‎The perfect Roman domination number of $G$‎, ‎denoted by $\gamma_{R}^{p}(G)$‎, ‎is‎

‎the minimum weight of a perfect Roman dominating function in $G$‎. ‎In this paper‎, ‎we study the‎

‎graphs for which adding any new edge decreases the perfect Roman‎

‎domination number‎. ‎We call these graphs $\gamma_R^p$-edge critical‎.

‎The purpose of this paper is to characterize the class of‎ ‎$\gamma_R^p$-edge critical trees‎.

Published
2019-05-24
Section
Articoli