ArticleOriginal scientific text
Title
On graphs with a unique minimum hull set
Authors 1, 1
Affiliations
- Department of Mathematics and Statistics, Western Michigan University, Kalamazoo, MI 49008, USA
Abstract
We show that for every integer k ≥ 2 and every k graphs G₁,G₂,...,Gₖ, there exists a hull graph with k hull vertices v₁,v₂,...,vₖ such that link for 1 ≤ i ≤ k. Moreover, every pair a, b of integers with 2 ≤ a ≤ b is realizable as the hull number and geodetic number (or upper geodetic number) of a hull graph. We also show that every pair a,b of integers with a ≥ 2 and b ≥ 0 is realizable as the hull number and forcing geodetic number of a hull graph.
Keywords
geodetic set, geodetic number, convex hull, hull set, hull number, hull graph
Bibliography
- F. Buckley and F. Harary, Distance in Graphs (Addison-Wesley, Redwood City, CA, 1990).
- G. Chartrand, F. Harary and P. Zhang, On the geodetic number of a graph, Networks, to appear.
- G. Chartrand, F. Harary and P. Zhang, On the hull number of a graph, Ars Combin. 57 (2000) 129-138.
- G. Chartrand and P. Zhang, The geodetic number of an oriented graph, European J. Combin. 21 (2) (2000) 181-189, doi: 10.1006/eujc.1999.0301.
- G. Chartrand and P. Zhang, The forcing geodetic number of a graph, Discuss. Math. Graph Theory 19 (1999) 45-58, doi: 10.7151/dmgt.1084.
- G. Chartrand and P. Zhang, The forcing hull number of a graph, J. Combin. Math. Combin. Comput. to appear.
- M.G. Everett and S.B. Seidman, The hull number of a graph, Discrete Math. 57 (1985) 217-223, doi: 10.1016/0012-365X(85)90174-8.
- F. Harary and J. Nieminen, Convexity in graphs, J. Differential Geom. 16 (1981) 185-190.
- F. Harary, E. Loukakis and C. Tsouros, The geodetic number of a graph, Mathl. Comput. Modelling. 17 (11) (1993) 89-95, doi: 10.1016/0895-7177(93)90259-2.
- H.M. Mulder, The Interval Function of a Graph (Methematisch Centrum, Amsterdam, 1980).
- H.M. Mulder, The expansion procedure for graphs, in: Contemporary Methods in Graph Theory ed., R. Bodendiek (Wissenschaftsverlag, Mannheim, 1990) 459-477.
- L. Nebeský, A characterization of the interval function of a connected graph, Czech. Math. J. 44 (119) (1994) 173-178.
- L. Nebeský, Characterizing of the interval function of a connected graph, Math. Bohem. 123 (1998) 137-144.