Vertex Clustering Coefficient

For a vertex of a simple, connected Undirected Graph:

cc(v):={mv(nv2)=2mvnv(nv−1) if δ(v)>1 undefined  otherwise c c(v):= \begin{cases}\frac{m_{v}}{\left(\begin{array}{c} n_{v} \\ 2 \end{array}\right)}=\frac{2 m_{v}}{n_{v}\left(n_{v}-1\right)} & \text { if } \delta(v)>1 \\ \text { undefined } & \text { otherwise }\end{cases}