 Laman graph

In graph theory, the Laman graphs are a family of sparse graphs describing the minimally rigid systems of rods and joints in the plane.Formally, a Laman graph is a graph on "n" vertices such that, for all "k", every "k"-vertex subgraph has at most 2"k" − 3 edges, and such that the whole graph has exactly 2"n" − 3 edges.