Article
Keywords:
connected graphs; distance; steps; geodetically smooth graphs
Summary:
If $G$ is a connected graph with distance function $d$, then by a step in $G$ is meant an ordered triple $(u, x, v)$ of vertices of $G$ such that $d(u, x) = 1$ and $d(u, v) = d(x, v) + 1$. A characterization of the set of all steps in a connected graph was published by the present author in 1997. In Section 1 of this paper, a new and shorter proof of that characterization is presented. A stronger result for a certain type of connected graphs is proved in Section 2.
References:
[2] G. Chartrand and L. Lesniak:
Graphs & Digraphs. Third edition. Chapman & Hall, London, 1996.
MR 1408678
[3] S. Klavžar and H. M. Mulder:
Median graphs: characterizations, location theory and related structures. J. Combin. Math. Combin. Comput. 30 (1999), 103–127.
MR 1705337
[4] H. M. Mulder:
The interval function of a graph. Math. Centre Tracts 132, Math. Centre, Amsterdam, 1980.
MR 0605838 |
Zbl 0446.05039
[5] H. M. Mulder and L. Nebeský:
Modular and median signpost systems and their underlying graphs. Discuss. Math. Graph Theory 23 (2003), 309–32444.
DOI 10.7151/dmgt.1204 |
MR 2070159
[9] L. Nebeský:
A tree as a finite nonempty set with a binary operation. Math. Bohem. 125 (2000), 455–458.
MR 1802293