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Graphs and combinatorics, 2022-08, Vol.38 (4), Article 125
Ort / Verlag
Tokyo: Springer Japan
Erscheinungsjahr
2022
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
Given a graph
G
(with multiple edges allowed), a
k-restricted edge-cut of G
is an edge-cut
R
⊆
E
(
G
)
of
G
such that every connected component in
G
-
R
has order at least
k
. A graph
G
is
λ
k
-
connected
if
k
-restricted edge cuts exist. Given an edge-coloring of
G
, an edge-cut of
G
will be called
heterochromatic
if all its edges receive different colors. Given a graph
G
and an integer
k
≥
2
, let
h
(
G
,
k
) be the minimum integer
p
such that every
p
-coloring of the edges of
G
produces an heterochromatic
k
-restricted edge-cut of
G
. In this paper we prove that for a
λ
k
-connected graph
G
of size
m
, order
n
≥
3
k
-
2
, and with no
k
-restricted edge-cut of size 1, we have that
m
-
n
+
min
{
κ
0
(
G
)
-
2
,
t
(
G
,
k
)
}
+
2
≤
h
(
G
,
k
)
≤
m
-
n
+
t
(
G
,
k
)
+
2
, where
κ
0
(
G
)
is the vertex-connectivity of
G
and
t
(
G
,
k
) is the maximum cardinality of a set
S
⊆
V
(
G
)
such that the connected components in
G
[
S
] have order at most
k
-
1
. As a corollary we see that
h
(
G
,
k
)
≤
m
-
n
+
α
(
G
)
(
k
-
1
)
+
2
, with
α
(
G
)
the independence number of
G
.