# On the outer independent 2-rainbow domination number of Cartesian products of paths and cycles

Document Type : Original paper

Author

Sirjan University of Technology, Sirjan 78137, Iran

10.22049/cco.2021.27067.1188

Abstract

‎Let G be a graph‎. ‎A 2-rainbow dominating function (or‎ 2-RDF) of G is a function f from V(G)
‎to the set of all subsets of the set {1,2}
‎such that for a vertex v ∈ V (G) with f(v) = ∅, ‎the‎
‎condition $bigcup_{uin N_{G}(v)}f(u)={1,2}$ is fulfilled‎, wher NG(v)  is the open neighborhood‎
‎of v‎. ‎The weight of 2-RDF f of G is the value‎
‎$omega (f):=sum _{vin V(G)}|f(v)|$‎. ‎The 2-rainbow‎
‎domination number of G‎, ‎denoted by Υr2 (G)‎, ‎is the‎
‎minimum weight of a 2-RDF of G‎. ‎A 2-RDF f is called an outer independent 2-rainbow dominating function ‎(or OI2-RDF) of G if‎
‎the set of all v ∈ V (G) with f(v) = ∅ is an‎
‎independent set‎.
‎The outer independent 2-rainbow domination number Υoir2  (G) is‎
‎the minimum weight of an OI2-RDF of G‎.
‎In this paper‎, ‎we obtain the‎
‎outer independent 2-rainbow domination number of Pm□Pn ‎and‎ Pm□Cn‎. ‎Also we determine the value of Υoir2  (Cm2Cn) when m or n is even‎.

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