Sparsity
Streinu & Theran (2008) define a graph as being -sparse if every nonempty subgraph with vertices has at most edges, and -tight if it is -sparse and has exactly edges. Thus, in their notation, the Laman graphs are exactly the (2,3)-tight graphs, and the subgraphs of the Laman graphs are exactly the (2,3)-sparse graphs. The same notation can be used to describe other important families of sparse graphs, including trees, pseudoforests, and graphs of bounded arboricity.
Read more about this topic: Laman Graph