engleski

On the eccentric complexity of graphs

Let $G$ be a simple connected graph. The eccentric complexity of graph $G$ is introduced as the number of different eccentricities of its vertices. A graph with eccentric complexity equal to one is called self-centered. In this paper, we study the eccentric complexity of graph under several graph operations such as complement of graph, line graph, Cartesian product, sum, disjunction and symmetric difference of graphs. Also, we present an infinite family of non-vertex-transitive self-centered graphs and we prove that all such graphs are 2-connected. Further, for any $D$ and $k$ where $k \le \frac{;D};{;2}; +1$, we construct an infinite family of non-vertex-transitive graphs with eccentric complexity $k$ and diameter $D$. Extremal graphs with minimum or maximum total eccentricity among all graphs with given eccentric complexity are determined. We also consider a family of of nanotubes and show that it is extremal with respect to the eccentric complexity among all fullerene graphs. At the end we also indicate some possible directions of further research.

eccentric complexity ; composite graph ; fullerene graph ; nanotube

nije evidentirano