Adjacency Matrix/Examples/Multigraph

Example of Adjacency Matrix
The elements of the adjacency matrix of a multigraph are integers, and the diagonal elements are all zero:

$\qquad \begin{pmatrix} 0 & 1 & 0 & 0 & 0 & 0 \\ 1 & 0 & 2 & 1 & 0 & 0 \\ 0 & 2 & 0 & 1 & 0 & 0 \\ 0 & 1 & 1 & 0 & 1 & 0 \\ 0 & 0 & 0 & 1 & 0 & 3 \\ 0 & 0 & 0 & 0 & 3 & 0 \\ \end{pmatrix}$