%0 Journal Article %T Non-commuting graphs of nilpotent groups %A Alireza Abdollahi %A Hamid Shahverdi %J Mathematics %D 2013 %I arXiv %X Let $G$ be a non-abelian group and $Z(G)$ be the center of $G$. The non-commuting graph $\Gamma_G$ associated to $G$ is the graph whose vertex set is $G\setminus Z(G)$ and two distinct elements $x,y$ are adjacent if and only if $xy\neq yx$. We prove that if $G$ and $H$ are non-abelian nilpotent groups with irregular isomorphic non-commuting graphs, then $|G|=|H|$. %U http://arxiv.org/abs/1304.4839v1