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Domination, radius, and minimum degree
We prove sharp bounds concerning domination number, radius, order and minimum degree of a graph. In particular, we prove that if G is a connected graph of order n , domination number γ and radius r , then 2 3 r ≤ γ ≤ n − 4 3 r + 2 3 . Equality is achieved in the upper bound if, and only if, G is a p...
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Published in: | Discrete Applied Mathematics 2009-07, Vol.157 (13), p.2964-2968 |
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Main Authors: | , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | We prove sharp bounds concerning domination number, radius, order and minimum degree of a graph. In particular, we prove that if
G
is a connected graph of order
n
, domination number
γ
and radius
r
, then
2
3
r
≤
γ
≤
n
−
4
3
r
+
2
3
. Equality is achieved in the upper bound if, and only if,
G
is a path or a cycle on
n
vertices with
n
≡
4
(
mod
6
)
. Further, if
G
has minimum degree
δ
≥
3
and
r
≥
6
, then using a result due to Erdös, Pach, Pollack, and Tuza [P. Erdös, J. Pach, R. Pollack, Z. Tuza, Radius, diameter, and minimum degree. J. Combin. Theory B 47 (1989), 73–79] we show that
γ
≤
n
−
2
3
(
r
−
6
)
δ
. |
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ISSN: | 0166-218X 1872-6771 |
DOI: | 10.1016/j.dam.2009.04.009 |