M. Tavakoli, F. Rahbarnia, M. Mirzavaziri, A. R. Ashrafi, I. Gutman

The irregularity of a graph $G$ is defined as $irr(G) =\sum |d(x)-d(y)|$ where $d(x)$ is the degree of vertex $x$ and the summation embraces all pairs of adjacent vertices of $G$. We characterize the graphs minimum and maximum values of $irr$.