Figure 1.
Top: the node n has v = 5 neighbours and t = 5 triangles, thus curvature curv(n) = 1/2, see Eq. (2). Bottom left: a complete graph, each node has curvature 1. Center: a tree, each node has curvature 0 or undefined. Right: the central node is a hub with curvature ≈ 1/v