An improvement on Vizing's conjecture
نویسنده
چکیده
Let γ(G) denote the domination number of a graph G. A Roman domination function of a graph G is a function f : V → {0, 1, 2} such that every vertex with 0 has a neighbor with 2. The Roman domination number γR(G) is the minimum of f(V (G)) = Σv∈V f(v) over all such functions. Let G H denote the Cartesian product of graphs G and H. We prove that γ(G)γ(H) ≤ γR(G H) for all simple graphs G and H, which is an improvement of γ(G)γ(H) ≤ 2γ(G H) given by Clark and Suen [1], since γ(G H) ≤ γR(G H) ≤ 2γ(G H).
منابع مشابه
An Improved Inequality Related to Vizing's Conjecture
Vizing conjectured in 1963 that γ(G2H) > γ(G)γ(H) for any graphs G and H. A graph G is said to satisfy Vizing’s conjecture if the conjectured inequality holds for G and any graph H. Vizing’s conjecture has been proved for γ(G) 6 3, and it is known to hold for other classes of graphs. Clark and Suen in 2000 showed that γ(G2H) > 12γ(G)γ(H) for any graphs G and H. We give a slight improvement of t...
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ورودعنوان ژورنال:
- Inf. Process. Lett.
دوره 113 شماره
صفحات -
تاریخ انتشار 2013