Strong domination number of some path related graphs

Let $G =(V, E)$ be a graph and $uv in E$ be an edge then $u$ strongly dominates $v$ if $deg(u) geq deg(v)$. A set $S$ is a $strong$ $dominating$ $set$ ($sd-set$) if every vertex $v in V-S$ is strongly dominated by some $u$ in $S$. We investigate strong domination number of some path related graphs.