Discussion:
Q: What bound is given for X(G) by the theorem "for every graph G" X(G)<=1+max &(G') ,where the maximum is taken over all induced subgraphs G' of G" in the case that G is
a) a tree?
b) an outerplanar graph.
Note: -&(G') this sign represent the minimum degree of G'. Yes it is that minimum
-A graph G is outerplanar if it can be embedded in the plane so that every vertex of G lies on the boundary of the exterior region. A graph G is outerplanar if and only if G=K1 is planar.A graph G is outerplanar if and only if it contains no subgraphs that is a subdivision of either k4 or k2,3.
A graph G is outerplanar of order n>=2 and size m, then m<=2n-3.
What does outerplanar graph?