Figure 11. W1 and W2 are LCL covers of a circle. Their intersection graphs G(W1) and G(W2) are digital 1-spheres. W3, W4 and W5 are LCL covers of a sphere. Their intersection graphs G(W3), G(W4) and G(W5) are digital 2-spheres. W6 is a non-LCL covers of a sphere. Its intersection graph G(W6) is not a digital 2-sphere

From

Graph Theoretical Models of Closed n-Dimensional Manifolds: Digital Models of a Moebius Strip, a Projective Plane a Klein Bottle and n-Dimensional Spheres

Alexander V. Evako

Applied Mathematics and Physics. 2017, 5(1), 19-27 doi:10.12691/amp-5-1-3