Editing Outerplanar graph (section)

===Other properties===
Outerplanar graphs have [[degeneracy (graph theory)|degeneracy]] at most two: every subgraph of an outerplanar graph contains a vertex with degree at most two.<ref>{{harvtxt|Lick|White|1970}}.</ref>

Outerplanar graphs have [[treewidth]] at most two, which implies that many graph optimization problems that are [[NP-complete]] for arbitrary graphs may be solved in [[polynomial time]] by [[dynamic programming]] when the input is outerplanar. More generally, ''k''-outerplanar graphs have treewidth O(''k'').<ref>{{harvtxt|Baker|1994}}.</ref>

Every outerplanar graph can be represented as an [[intersection graph]] of axis-aligned rectangles in the plane, so outerplanar graphs have [[boxicity]] at most two.<ref>{{harvtxt|Scheinerman|1984}}; {{harvtxt|Brandstädt|Le|Spinrad|1999}}, p. 54.</ref>