Outer independent double Roman domination number of graphs

Doost Ali Mojdeh, Babak Samadi, Zehui Shao +1

A double Roman dominating function of a graph $G$ is a function $f:V(G)\to \{0,1,2,3\}$ having the property that for each vertex $v$ with $f(v)=0$, there exists $u\in N(v)$…