This may also be called
Matrice d’incidence. It's mainly used in directed graphs as an amelioration of the adjacency matrix because we lost some information.
This is a matrix vertex by vertex too, and the values are -1, 0, or 1. If we are at row=A, col=B
- -1: an arc is leaving A ($A \to B$)
- 1: an arc is entering A ($B \to A$)
- 0: no arc ($A \to B$ or $B \to A$)
If you can pick either -1 or 1, pick the one you want.
The incidence matrix for
Note: if you remove all the minus (
-) before the ones then you got the adjacency matrix for the undirected graph.