An incidence matrix M is the #vertexSet of G by #edges of G matrix where entry (i,j) equals 1 if vertex i is incident to edge j, and equals 0 otherwise.
i1 : M = incidenceMatrix cycleGraph 3
o1 = | 1 1 0 |
| 1 0 1 |
| 0 1 1 |
3 3
o1 : Matrix ZZ <--- ZZ
|