Vizing's conjecture and the one-half argument
Discussiones Mathematicae. Graph Theory, Tome 15 (1995) no. 2, pp. 205-216
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The domination number of a graph G is the smallest order, γ(G), of a dominating set for G. A conjecture of V. G. Vizing [5] states that for every pair of graphs G and H, γ(G☐H) ≥ γ(G)γ(H), where G☐H denotes the Cartesian product of G and H. We show that if the vertex set of G can be partitioned in a certain way then the above inequality holds for every graph H. The class of graphs G which have this type of partitioning includes those whose 2-packing number is no smaller than γ(G)-1 as well as the collection of graphs considered by Barcalkin and German in [1]. A crucial part of the proof depends on the well-known fact that the domination number of any connected graph of order at least two is no more than half its order.
Keywords:
domination number, Cartesian product, Vizing's conjecture, clique
@article{DMGT_1995_15_2_a7,
author = {Hartnell, Bert and Rall, Douglas},
title = {Vizing's conjecture and the one-half argument},
journal = {Discussiones Mathematicae. Graph Theory},
pages = {205--216},
year = {1995},
volume = {15},
number = {2},
language = {en},
url = {http://geodesic.mathdoc.fr/item/DMGT_1995_15_2_a7/}
}
Hartnell, Bert; Rall, Douglas. Vizing's conjecture and the one-half argument. Discussiones Mathematicae. Graph Theory, Tome 15 (1995) no. 2, pp. 205-216. http://geodesic.mathdoc.fr/item/DMGT_1995_15_2_a7/
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