How to Use
Select graph:
- ξ: Coarseness
- =0?: Planar?
- Disjoint: Edge-disjoint
Complete Graphs
K_n: ξ = ⌊(n+1)(n-3)/12⌋. Beautiful closed form! Each non-planar subgraph needs ≥9 edges (K_{3,3} or ≥10 for K_5). Elegant number theory connections.
Dual of Skewness
Skewness: minimum edges to remove for planarity. Coarseness: maximum non-planar 'packing'. Related: sk(G) ≥ 9·ξ(G) - 3 approximately. Both measure non-planarity from opposite perspectives.
Step-by-Step Instructions
- 1Select graph.
- 2Compute ξ.
- 3Pack non-planar.
- 4Compare with sk.
- 5Apply formula.