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Incidence matrix
Set
$n_v,m_e\in \mathbb N$ |
$ M\in \mathrm{it}(n_v,m_e) $ |
$ \mathrm{Matrix}(n_v,m_e,\{0,1,2\}) $ |
$i\in\mathrm{range}(n_v)$ |
$\sum_{j=1}^{m_e} M_{ij}=2 $ |
Discussion
The index $i$ in $M_{ij}$ labels the vertices and the index $j$ labels the edges. The definition says that every edge has exactly two endpoints.
Every incidence matrix corresponds to (a representative of the isomorphism class of) a finite undirected graph.