While the Euler characteristic χ(G) = ω1(G) = ∑ x ω(x) super counts simplices, the Wu characteristics ωk(G) = ∑ x1∼x2···∼xk ω(x1) · · ·ω(xk) super counts simultaneously pairwise interacting k-tuples of simplices in a finite abstract simplicial complex G. More generally, one can define the k-intersection number ωk(G1, . . . Gk), which is the same sum but where xi ∈ Gi. For every k ≥ 1 we define ...