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Kragujevac Journal of Mathematics
Volume 37(1) (2013), Pages 163–186.
F -GEOMETRIC MEAN LABELING OF SOME CHAIN GRAPHSAND THORN GRAPHS
A. DURAI BASKAR, S. AROCKIARAJ AND B. RAJENDRAN
Abstract. A function f is called a F -Geometric mean labeling of a graph G(V,E)if f : V (G) → {1, 2, 3, . . . , q + 1} is injective and the induced function f∗ : E(G) →{1, 2, 3, . . . , q} defined as f∗(uv) =
⌊√f(u)f(v)
⌋, for all uv ∈ E(G), is bijective.
A graph that admits a F -Geometric mean labelling is called a F -Geometric meangraph. In this paper, we have discussed the F -Geometric mean labeling of somechain graphs and thorn graphs.
1. Introduction
Throughout this paper, by a graph we mean a finite, undirected and simple graph.Let G(V,E) be a graph with p vertices and q edges. For notations and terminology,we follow [3]. For a detailed survey on graph labeling, we refer [2].
Path on n vertices is denoted by Pn and a cycle on n vertices is denoted by Cn.G ⊙ K1 is the graph obtained from G by attaching a new pendant vertex to eachvertex of G. A star graph Sm is the complete bipartite graph K1,m. G ⊙ S2 is thegraph obtained from G by attaching two pendant vertices at each vertex of G. If
v(i)1 , v
(i)2 , v
(i)3 , . . . , v
(i)m+1 and u1, u2, u3 . . . , un be the vertex of the star graph Sm and the
path Pn, then the graph (Pn;Sm) is obtained from n copies of Sm and the path Pn by
joining ui with the central vertex v(i)1 of the ith copy of Sm by means of an edge, for
1 ≤ i ≤ n. The H− graph is obtained from two paths u1, u2, . . . , un and v1, v2, . . . , vnof equal length by joining an edge un+1
2
vn+1
2
when n is odd and un+2
2
vn2when n is
even. Let G1 and G2 be any two graphs with p1 and p2 vertices, respectively. Thenthe cartesian product G1 × G2 has p1p2 vertices which are {(u, v)/u ∈ G1, v ∈ G2}.The edges are defined as follows: (u1, v1) and (u2, v2) are adjacent in G1×G2 if either
Key words and phrases. Labeling, F -Geometric mean labeling, F -Geometric mean graph.2010 Mathematics Subject Classification. 05C78.Received: February 18, 2012.Revised: January 29, 2013.
163
164 A. DURAI BASKAR, S. AROCKIARAJ AND B. RAJENDRAN
u1 = u2 and v1 and v2 are adjacent in G2 or u1 and u2 are adjacent in G1 and v1 = v2.The Ladder graph Ln is obtained from Pn × P2.
The study of graceful graphs and graceful labeling methods first introduced by Rosa[5]. The concept of mean labeling was first introduced by S. Somasundaram and R.Ponraj [6] and it was developed in [4] and [7]. In [10], R. Vasuki et al. discussedthe mean labeling of cyclic snake and armed crown. In [8], S. Somasundaram et al.defined the geometric mean labeling as follows.
A graphG = (V,E) with p vertices and q edges is said to be a geometric mean graphif it is possible to label the vertices x ∈ V with distinct labels f(x) from 1, 2, . . . , q+1
in such way that when each edge e = uv is labeled with f(uv) =⌊√
f(u)f(v)⌋or
⌈√f(u)f(v)
⌋then the edge labels are distinct.
In the above definition, the readers will get some confusion in finding the edgelabels which edge is assigned by flooring function and which edge is assigned byceiling function.
In [9], they have given the geometric mean labeling of the graph C5 ∪C7 as in theFigure 1.
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q q
1
1
2
3
3 4 4
5
5
2 6 6 7
7
8
9
910101111
12
12
8 u
v
w
Figure 1. A Geometric mean labeling of C5 ∪ C7.
From the above figure, for the edge uv, they have used flooring function⌊√
f(u)f(v)⌋
and for the edge vw, they have used ceiling function⌈√
f(u)f(v)⌉for fulfilling their
requirement. To avoid the confusion of assigning the edge labels in their definition,
we just consider the flooring function⌊√
f(u)f(v)⌋for our discussion. Based on
our definition, the F -Geometric mean labeling of the same graph C5 ∪ C7 is given inFigure 2.
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q q
q q
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q q
q q
q q
12
7
5
5
4
4
3
3
16
79
9
11
11
13
12
12
10
10
8
86
Figure 2. A F -Geometric mean labeling of C5 ∪ C7
In [1], A. Durai Baskar et al. introduced Geometric mean graph.A function f is called a F -Geometric mean labeling of a graph G(V,E) if
f : V (G) → {1, 2, 3, . . . , q + 1} is injective and the induced function f ∗ : E(G) →
F -GEOMETRIC MEAN LABELING OF SOME CHAIN GRAPHS AND THORN GRAPHS 165
{1, 2, 3, . . . , q} defined as
f ∗(uv) =⌊√
f(u)f(v)⌋, for all uv ∈ E(G),
is bijective. A graph that admits a F -Geometric mean labeling is called a F -Geometricmean graph.
The graph shown in Figure 3 is a F -Geometric mean graph.
rr
r r r
rrr
r r
rr
1
1
2
2
33571010111112
12
14
15
17
14
16
4
516
139
9 8 8
6
Figure 3. A F -Geometric mean graph
In this paper, we have discussed the F -Geometric mean labeling of some chaingraphs and thorn graphs.
2. Main Results
The graph G∗(p1, p2, . . . , pn) is obtained from n cycles of length p1, p2, . . . , pn byidentifying consecutive cycles at a vertex as follows. If the jth cycle is of odd length,
then its(
pj+3
2
)th
vertex is identified with the first vertex of (j + 1)th cycle and if the
jth cycle is of even length, then its(
pj+2
2
)th
vertex is identified with the first vertex
of (j + 1)th cycle.
Theorem 2.1. G∗(p1, p2, . . . , pn) is a F -Geometric mean graph for any pj, for
1 ≤ j ≤ n.
Proof. Let {v(j)i ; 1 ≤ j ≤ n, 1 ≤ i ≤ pj} be the vertices of the n number of cycles.
For 1 ≤ j ≤ n− 1, the jth and (j + 1)th cycles are identified by a vertex v(j)pj+3
2
and
v(j+1)1 while pj is odd and v
(j)pj+2
2
and v(j+1)1 while pj is even.
We define f : V [G∗(p1, p2, . . . , pn] →{1, 2, 3, . . . ,
n∑j=1
pj + 1
}as follows:
f(v(1)i ) =
{2i− 1 1 ≤ i ≤
⌊p12
⌋+ 1
2p1 − 2(i− 2)⌊p12
⌋+ 2 ≤ i ≤ p1
and
166 A. DURAI BASKAR, S. AROCKIARAJ AND B. RAJENDRAN
for 2 ≤ j ≤ n,
f(v(j)i ) =
j−1∑k=1
pk + 2i− 1 2 ≤ i ≤⌊pj
2
⌋+ 1
j−1∑k=1
pk + 2(i− 1) i =⌊pj
2
⌋+ 2 and pj is odd
j−1∑k=1
pk + 2(i− 2) i =⌊pj
2
⌋+ 2 and pj is even
j−1∑k=1
pk + 2pj − 2(i− 2) i =⌊pj
2
⌋+ 3 ≤ i ≤ pj
The induced edge labeling is as follows:
f ∗(v(1)i v
(1)i+1) =
2i− 1 1 ≤ i ≤⌊p12
⌋
2i− 1 i =⌊p12
⌋+ 1 and p1 is odd
2p1 − 2(i− 1) i =⌊p12
⌋+ 1 and p1 is even
2p1 − 2(i− 1)⌊p12
⌋+ 2 ≤ i ≤ p1 − 1,
f ∗(v(1)p1v(1)1 ) = 2,
for 2 ≤ j ≤ n,
f ∗(v(j)i v
(j)i+1) =
j−1∑k=1
pk + 2i− 1 1 ≤ i ≤⌊pj
2
⌋
j−1∑k=1
pk + 2i− 1 i =⌊pj
2
⌋+ 1 and pj is odd
j−1∑k=1
pk + 2pj − 2(i− 1) i =⌊pj
2
⌋+ 1 and pj is even
j−1∑k=1
pk + 2pj − 2(i− 1)⌊pj
2
⌋+ 2 ≤ i ≤ pj − 1
and
f ∗(v(j)pjv(j)1 ) =
j−1∑
k=1
pk + 2.
Hence, f is a F -Geometric mean labeling of G∗(p1, p2, . . . , pn). Thus the graphG∗(p1, p2, . . . , pn) is a F -Geometric mean graph. �
A F -Geometric mean labeling of G∗(10, 9, 12, 4, 5) is as shown in Figure 4.
F -GEOMETRIC MEAN LABELING OF SOME CHAIN GRAPHS AND THORN GRAPHS 167
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Figure 4. A F -Geometric mean labeling of G∗(10, 9, 12, 4, 5)
The graph G′(p1, p2, . . . , pn) is obtained from n cycles of length p1, p2, . . . , pn by iden-
tifying consecutive cycles at an edge as follows: The(
pj+3
2
)th
edge of jth cycle is
identified with the first edge of (j + 1)th cycle when j is odd and the(
pj+1
2
)th
edge
of jth cycle is identified with the first edge of (j + 1)th cycle when j is even.
Theorem 2.2. G′(p1, p2, . . . , pn) is a F -Geometric mean graph if all pj’s are odd or
all pj’s are even, for 1 ≤ j ≤ n.
Proof. Let {v(j)i ; 1 ≤ j ≤ n, 1 ≤ i ≤ pj} be the vertices of the n number of cycles.
Case (i) pj is odd, for 1 ≤ j ≤ n.For 1 ≤ j ≤ n − 1, the jth and (j + 1)th cycles are identified by the edges
v(j)pj+1
2
v(j)pj+3
2
and v(j+1)1 v
(j+1)pj+1 while j is odd and v
(j)pj−1
2
v(j)pj+1
2
and v(j+1)1 v
(j+1)pj+1 while j is
even.
We define f : V [G′(p1, p2, . . . , pn)] →{1, 2, 3, . . . ,
n∑j=1
pj − n + 2
}as follows:
f(v(1)i ) =
1 i = 12i 2 ≤ i ≤
⌊p12
⌋+ 1
2p1 + 3− 2i⌊p12
⌋+ 2 ≤ i ≤ p1
and for 2 ≤ j ≤ n,
f(v(j)i ) =
j−1∑k=1
pk − j + 2i+ 2 2 ≤ i ≤⌊pj
2
⌋and j is even
j−1∑k=1
pk + 2pj + 3− j − 2i⌊pj
2
⌋+ 1 ≤ i ≤ pj − 1 and j even
j−1∑k=1
pk − j + 2i+ 1 2 ≤ i ≤⌊pj
2
⌋+ 1 and j is odd
j−1∑k=1
pk + 2pj + 4− j − 2i⌊pj
2
⌋+ 2 ≤ i ≤ pj − 1 and j odd.
168 A. DURAI BASKAR, S. AROCKIARAJ AND B. RAJENDRAN
The induced edge labeling is as follows:
f ∗(v(1)i v
(1)i+1) =
{2i 1 ≤ i ≤
⌊p12
⌋
2p1 + 1− 2i⌊p12
⌋+ 1 ≤ i ≤ p1 − 1,
f ∗(v(1)p1v(1)1 ) = 1
and for 2 ≤ j ≤ n,
f ∗(v(j)i v
(j)i+1) =
j−1∑k=1
pk − j + 2i+ 2 1 ≤ i ≤⌊pj
2
⌋and j is even
j−1∑k=1
pk + 2pj + 1− j − 2i⌊pj
2
⌋+ 1 ≤ i ≤ pj − 1 and j even
j−1∑k=1
pk − j + 2i+ 1 1 ≤ i ≤⌊pj
2
⌋and j is odd
j−1∑k=1
pk + 2pj + 2− j − 2i⌊pj
2
⌋+ 1 ≤ i ≤ pj − 1 and j odd.
Case (ii) pj is even, for 1 ≤ j ≤ n.For 1 ≤ j ≤ n − 1, the jth and (j + 1)th cycles are identified by the edges
v(j)pj
2
v(j)pj+2
2
and v(j+1)1 v
(j+1)pj+1
.
We define f : V [G′(p1, p2, . . . , pn)] →{1, 2, 3, . . . ,
n∑j=1
pj − n+ 2
}as follows:
f(v(1)i ) =
1 i = 12i 2 ≤ i ≤
⌊p12
⌋
2p1 + 3− 2i⌊p12
⌋+ 1 ≤ i ≤ p1
and for 2 ≤ j ≤ n,
f(v(j)i ) =
j−1∑k=1
pk − j + 2i+ 1 2 ≤ i ≤⌊pj
2
⌋
j−1∑k=1
pk + 2pj + 4− j − 2i⌊pj
2
⌋+ 1 ≤ i ≤ pj − 1.
The induced edge labeling is as follows:
f ∗(v(1)i v
(1)i+1) =
{2i 1 ≤ i ≤
⌊p12
⌋
2p1 + 1− 2i⌊p12
⌋+ 1 ≤ i ≤ p1 − 1,
f ∗(v(1)p1v(1)1 ) = 1
F -GEOMETRIC MEAN LABELING OF SOME CHAIN GRAPHS AND THORN GRAPHS 169
and for 2 ≤ j ≤ n,
f ∗(v(j)i v
(j)i+1) =
j−1∑k=1
pj − j + 2i+ 1 1 ≤ i ≤⌊pj
2
⌋
j−1∑k=1
pk + 2pj + 2− j − 2i⌊pj
2
⌋+ 1 ≤ i ≤ pj − 1.
Hence, f is a F -Geometric mean labeling of G′(p1, p2, . . . , pn). Thus the graphG′(p1, p2, . . . , pn) is a F -Geometric mean graph. �
A F -Geometric mean labeling of G′(7, 5, 9, 13) and G′(4, 8, 10, 6) is as shown inFigure 5.
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14 14
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16 18
1820
2021
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1917
17
1515
13
21
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25
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22
Figure 5. F -Geometric mean labeling of G′(7, 5, 9, 13) and G′(4, 8, 10, 6)
The graph G(p1, m1, p2, m2, . . . , mn−1, pn) is obtained from n cycles of lengthp1, p2, . . . , pn and (n − 1) paths on m1, m2, . . . , mn−1 vertices respectively by iden-tifying a cycle and a path at a vertex alternatively as follows: If the jth cycles is of
odd length, then its(
pj+3
2
)th
vertex is identified with a pendant vertex of jth path
and if the jth cycle is of even length, then its(
pj+2
2
)th
vertex is identified with a
pendant vertex of jth path while the other pendant vertex of the jth path is identifiedwith the first vertex of the (j + 1)th cycle.
Theorem 2.3. G(p1, m1, p2, m2, . . . , mn−1pn) is a F -Geometric mean graph for any
pj’s and mj’s.
Proof. Let {v(j)i ; 1 ≤ j ≤ n, 1 ≤ i ≤ pj} and {u(j)i ; 1 ≤ j ≤ n− 1, 1 ≤ i ≤ mj} be the
n number of cycles and (n− 1) number of paths respectively.
170 A. DURAI BASKAR, S. AROCKIARAJ AND B. RAJENDRAN
For 1 ≤ j ≤ n − 1, the jth cycle and jth path are identified by a vertex v(j)pj+2
2
and
u(j)1 while pj is even and v
(j)pj+3
2
and u(j)1 while pj is odd. And the jth path and (j+1)th
cycle are identified by a vertex u(j)mj and v
(j+1)1 .
We define f : V [G(p1, m1, p2, m2, . . . , mn−1, pn)] →{1, 2, 3, . . . ,
n−1∑j=1
(pj +mj)+ pn −
n+ 2}as follows:
f(v(1)i ) =
{2i− 1 1 ≤ i ≤
⌊p12
⌋+ 1
2p1 + 4− 2i⌊p12
⌋+ 2 ≤ i ≤ p1,
f(u(1)i ) = p1 + i, for 2 ≤ i ≤ m1,
for 2 ≤ j ≤ n,
f(v(j)i ) =
j−1∑k=1
(pk +mk) + 2i− j 2 ≤ i ≤⌊pj
2
⌋+ 1
j−1∑k=1
(pk +mk) + 2i− j − 1 i =⌊pj
2
⌋+ 2
and pj is odd
j−1∑k=1
(pk +mk) + 2i− j − 3 i =⌊pj
2
⌋+ 2 and
pj is even
j−1∑k=1
(pk +mk) + 2pj − 2i− j + 5⌊pj
2
⌋+ 3 ≤ i ≤ pj
and for 3 ≤ j ≤ n,
f(u(j−1)i ) =
j−2∑
k=1
(pk +mk) + pj−1 + i+ 2− j, for 2 ≤ i ≤ mj−1
The induced edge labeling is as follows:
f ∗(v(1)i v
(1)i+1) =
2i− 1 1 ≤ i ≤⌊p12
⌋
2i− 1 i =⌊p12
⌋+ 1 and
p1 is odd2p1 − 2i+ 2 i =
⌊p12
⌋+ 1 and
p1 is even2p1 − 2i+ 2
⌊p12
⌋+ 2 ≤ i ≤ p1 − 1,
f ∗(v(1)p1v(1)1 ) = 2,
f ∗(u(1)i u
(1)i+1) = p1 + i, for 1 ≤ i ≤ m1 − 1,
F -GEOMETRIC MEAN LABELING OF SOME CHAIN GRAPHS AND THORN GRAPHS 171
for 2 ≤ j ≤ n,
f ∗(v(j)i v
(j)i+1) =
j−1∑k=1
(pk +mk) + 2i− j 1 ≤ i ≤⌊pj
2
⌋
j−1∑k=1
(pk +mk) + 2i− j i =⌊pj
2
⌋+ 1 and
pj is odd
j−1∑k=1
(pk +mk) + 2pj − 2i− j + 3 i =⌊pj
2
⌋+ 1 and
pj is even
j−1∑k=1
(pk +mk) + 2pj − 2i− j + 3⌊pj
2
⌋+ 2 ≤ i ≤ pj − 1,
f ∗(v(j)pjv(j)1 ) =
j−1∑
k=1
(pk +mk)− j + 3
and for 3 ≤ j ≤ n,
f ∗(u(j−1)i u
(j−1)i+1 ) =
j−2∑
k=1
(pk +mk) + pj−1 + i+ 2− j, for 1 ≤ i ≤ mj−1 − 1.
Hence, f is a F -Geometric mean labeling of G(p1, m1, p2, m2 . . . , mn−1, pn). Thus the
graph G(p1, m1, p2, m2 . . . , mn−1, pn) is a F -Geometric mean graph. �
A F -Geometric mean labeling of G(8, 4, 5, 6, 10) is as shown in Figure 6.
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r
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r
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r
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r
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r
r
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Figure 6. A F -Geometric mean labeling of G(8, 4, 5, 6, 10)
Theorem 2.4. Cn ⊙K1 is a F -Geometric mean graph, for n ≥ 3.
Proof. Let v1, v2, . . . , vn be the vertices of the cycle Cn and let ui be the pendantvertices attached at each vi, for 1 ≤ i ≤ n. Consider the graph Cn ⊙K1, for n ≥ 4.Case (i)
⌊√2n+ 1
⌋is odd.
172 A. DURAI BASKAR, S. AROCKIARAJ AND B. RAJENDRAN
We define f : V [Cn ⊙K1] → {1, 2, 3, . . . , 2n+ 1} as follows:
f(vi) =
1 i = 1
2i 2 ≤ i ≤⌊√
2n+12
⌋+ 1
2i+ 1⌊√
2n+12
⌋+ 2 ≤ i ≤ n
and
f(ui) =
2 i = 1
2i− 1 2 ≤ i ≤⌊√
2n+12
⌋
2i+ 1 i =⌊√
2n+12
⌋+ 1
2i⌊√
2n+12
⌋+ 2 ≤ i ≤ n.
The induced edge labeling is as follows:
f ∗(vivi+1) =
2i 1 ≤ i ≤⌊√
2n+12
⌋
2i+ 1⌊√
2n+12
⌋+ 1 ≤ i ≤ n− 1,
f ∗(v1vn) =⌊√
2n+ 1⌋
and
f ∗(uivi) =
2i− 1 1 ≤ i ≤⌊√
2n+12
⌋
2i⌊√
2n+12
⌋+ 1 ≤ i ≤ n.
Case (ii)⌊√
2n+ 1⌋is even.
We define f : V [Cn ⊙K1] → {1, 2, 3, . . . , 2n+ 1} as follows:
f(vi) =
1 i = 1
2i 2 ≤ i ≤⌊√
2n+12
⌋
2i+ 1⌊√
2n+12
⌋+ 1 ≤ i ≤ i ≤ n
and
f(ui) =
2 i = 1
2i− 1 2 ≤ i ≤⌊√
2n+12
⌋
2i⌊√
2n+12
⌋+ 1 ≤ i ≤ n.
The induced edge labeling is as follows:
f ∗(vivi+1) =
2i 1 ≤ i ≤⌊√
2n+12
⌋− 1
2i+ 1⌊√
2n+12
⌋≤ i ≤ n− 1,
f ∗(v1vn) =⌊√
2n+ 1⌋
and
f ∗(uivi) =
2i− 1 1 ≤ i ≤⌊√
2n+12
⌋
2i⌊√
2n+12
⌋+ 1 ≤ i ≤ n.
F -GEOMETRIC MEAN LABELING OF SOME CHAIN GRAPHS AND THORN GRAPHS 173
Hence, the graph Cn ⊙K1, for n ≥ 4 admits F -Geometric mean labeling. �
For n = 3, a F -Geometric mean labeling of C3 ⊙K1 is as shown in Figure 7.r
r
r r rr
1
1
2
3
76
65445
2
Figure 7. A F - Geometric mean labeling of C3 ⊙K1
A F -Geometric mean labeling of C12 ⊙K1 is as shown in Figure 8.
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r
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r
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Figure 8. A F -Geometric mean labeling of C12 ⊙K1
Theorem 2.5. Cn ⊙ S2 is a F -Geometric mean graph for n ≥ 3.
Proof. Let u1, u2, . . . , un be the vertices of the cycle Cn. Let v(i)1 be the pendant
vertices at each vertex ui, for 1 ≤ i ≤ n. Therefore,
V [Cn ⊙ S2] = V (Cn) ∪ {v(i)1 , v(i)2 ; 1 ≤ i ≤ n}
andE[Cn ⊙ S2] = E(Cn) ∪ {uiv
(i)1 , uiv
(i)2 ; 1 ≤ i ≤ n}.
174 A. DURAI BASKAR, S. AROCKIARAJ AND B. RAJENDRAN
Case (i)⌊√
6n⌋is a multiple of 3.
We define f : V [Cn ⊙ S2] → {1, 2, 3, . . . , 3n+ 1} as follows:
f(ui) =
3i− 1 1 ≤ i ≤⌊√
6n3
⌋
3i+ 1 i =⌊√
6n3
⌋+ 1
3i⌊√
6n3
⌋+ 2 ≤ i ≤ n,
f(v(i)1 ) =
3i− 2 1 ≤ i ≤⌊√
6n3
⌋
3i− 1⌊√
6n3
⌋+ 1 ≤ i ≤ n
and
f(v(i)2 ) =
3i 1 ≤ i ≤⌊√
6n3
⌋+ 1
3i+ 1⌊√
6n3
⌋+ 2 ≤ i ≤ n.
The induced edge labeling is as follows
f ∗(uiui+1) =
3i 1 ≤ i ≤⌊√
6n3
⌋− 1
3i+ 1⌊√
6n3
⌋≤ i ≤ n− 1,
f ∗(unu1) =⌊√
6n⌋,
f ∗(uiv(i)1 ) =
3i− 2 1 ≤ i ≤⌊√
6n3
⌋
3i− 1⌊√
6n3
⌋+ 1 ≤ i ≤ n
and
f ∗(uiv(i)2 ) =
3i− 1 1 ≤ i ≤⌊√
6n3
⌋
3i⌊√
6n3
⌋+ 1 ≤ i ≤ n.
Case (ii)⌊√
6n⌋is not a multiple of 3.
We define f : V [Cn ⊙ S2] → {1, 2, 3, . . . , 3n+ 1} as follows:
f(ui) =
3i− 1 1 ≤ i ≤⌊√
6n3
⌋
3i⌊√
6n3
⌋+ 1 ≤ i ≤ n,
f(v(i)1 ) =
3i− 2 1 ≤ i ≤⌊√
6n+13
⌋
3i− 1⌊√
6n+13
⌋+ 1 ≤ i ≤ n
F -GEOMETRIC MEAN LABELING OF SOME CHAIN GRAPHS AND THORN GRAPHS 175
and
f(v(i)2 ) =
3i 1 ≤ i ≤⌊√
6n3
⌋
3i+ 1⌊√
6n3
⌋+ 1 ≤ i ≤ n.
The induced edge labeling is as follows
f ∗(uiui+1) =
3i 1 ≤ i ≤⌊√
6n3
⌋
3i+ 1⌊√
6n3
⌋+ 1 ≤ i ≤ n− 1,
f ∗(unu1) =⌊√
6n⌋,
f ∗(uiv(i)1 ) =
3i− 2 1 ≤ i ≤⌊√
6n+13
⌋
3i− 1⌊√
6n+13
⌋+ 1 ≤ i ≤ n
and
f ∗(uiv(i)2 ) =
3i− 1 1 ≤ i ≤⌊√
6n3
⌋
3i⌊√
6n3
⌋+ 1 ≤ i ≤ n.
Hence, f is a F -Geometric mean labeling of Cn ⊙ S2. Thus the graph Cn ⊙ S2 is aF -Geometric mean graph, for n ≥ 3. �
A F -Geometric mean labeling of C6 ⊙ S2 is as shown in Figure 9.
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Figure 9. A F -Geometric mean labeling of C6 ⊙ S2
Theorem 2.6. (Pn;Sm) is a F -Geometric mean graph, for m ≤ 2 and n ≥ 1.
Proof. Let u1, u2, . . . , un be the vertices of the path Pn and Let v(i)1 , v
(i)2 , . . . , v
(i)m+1
be the vertices of the star graph Sm such that v(i)1 is the central vertex of Sm, for
1 ≤ i ≤ n.
176 A. DURAI BASKAR, S. AROCKIARAJ AND B. RAJENDRAN
Case (i) m = 1We define f : V [(Pn;Sm)] → {1, 2, 3, . . . , 3n} as follows:
f(ui) =
{3i 1 ≤ i ≤ n and i is odd3i− 2 1 ≤ i ≤ n and i is even,
f(v(i)1 ) = 3i− 1, for 1 ≤ i ≤ n
and
f(v(i)2 ) =
{3i− 2 1 ≤ i ≤ n and i is odd3i 1 ≤ i ≤ n and i is even.
The induced edge labeling is as follows
f ∗(uiui+1) = 3i, for 1 ≤ i ≤ n− 1,
f ∗(uiv(i)1 ) =
{3i− 1 1 ≤ i ≤ n and i is odd3i− 2 1 ≤ i ≤ n and i is even
and
f ∗(v(i)1 v
(i)2 ) =
{3i− 2 1 ≤ i ≤ n and i is odd3i− 1 1 ≤ i ≤ n and i is even.
Case (ii) m = 2We define f : V [(Pn;Sm)] → {1, 2, 3, . . . , 4n} as follows:
f(ui) =
{4i 1 ≤ i ≤ n and i is odd4i− 2 1 ≤ i ≤ n and i is even,
f(v(i)1 ) = 4i− 1, for 1 ≤ i ≤ n,
f(v(i)2 ) = 4i− 3, for 1 ≤ i ≤ n
and
f(v(i)3 ) =
{4i− 2 1 ≤ i ≤ n and i is odd4i 1 ≤ i ≤ n and i is even.
The induced edge labeling is as follows:
f ∗(uiui+1) = 4i, for 1 ≤ i ≤ n− 1,
f ∗(uiv(i)1 ) =
{4i− 1 1 ≤ i ≤ n and i is odd4i− 2 1 ≤ i ≤ n and i is even
f ∗(v(i)1 v
(i)2 ) = 4i− 3, for 1 ≤ i ≤ n
and
f ∗(v(i)1 v
(i)3 ) =
{4i− 2 1 ≤ i ≤ n and i is odd4i− 1 1 ≤ i ≤ n and i is even.
Hence, f is a F -Geometric mean labeling of (Pn;Sm.) Thus the graph (Pn;Sm) isa F -Geometric mean graph, for m ≤ 2 and n ≥ 1. �
A F -Geometric mean labeling of (P7;S1) and (P8;S2) is as shown in Figure 10.
F -GEOMETRIC MEAN LABELING OF SOME CHAIN GRAPHS AND THORN GRAPHS 177
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Figure 10. A F -Geometric mean labeling of (P7;S1) and (P8;S2)
Theorem 2.7. For a H−graph G, G⊙K1 is a F -Geometric mean graph.
Proof. Let u1, u2, . . . , un and v1, v2, . . . , vn be the vertices of G. Therefore
V (G⊙K1) = V (G) ∪ {u′i, v
′i; 1 ≤ i ≤ n}
and
E(G⊙K1) = E(G) ∪ {uiu′i, viv
′i; 1 ≤ i ≤ n}.
Case (i) n ≡ 0(mod 4).We define f : V (G⊙K1) → {1, 2, 3, . . . , 4n} as follows:
f(ui) =
{2i− 1 1 ≤ i ≤ n and i is odd2i 1 ≤ i ≤ n and i is even,
f(u′i) =
{2i 1 ≤ i ≤ n and i is odd2i− 1 1 ≤ i ≤ n and i is even,
f(vi) =
{2n− 3 + 4i 1 ≤ i ≤
⌊n2
⌋− 1 and i is odd
2n− 1 + 4i 1 ≤ i ≤⌊n2
⌋and i is even,
f(vn+1−i) =
{2n− 2 + 4i 1 ≤ i ≤
⌊n2
⌋− 1 and i is odd
2n+ 4i 1 ≤ i ≤⌊n2
⌋and i is even,
178 A. DURAI BASKAR, S. AROCKIARAJ AND B. RAJENDRAN
and
f(v′i) =
f(vi) + 2 1 ≤ i ≤⌊n2
⌋− 1 and i is odd
f(vi)− 2⌊n2
⌋+ 1 ≤ i ≤ n and i is odd
f(vi)− 2 1 ≤ i ≤⌊n2
⌋and i is even
f(vi) + 2⌊n2
⌋+ 2 ≤ i ≤ n and i is even.
The induced edge labeling is as follows:
f ∗(uiui+1) = 2i, for 1 ≤ i ≤ n− 1,
f ∗(uiu′i) = 2i− 1, for 1 ≤ i ≤ n,
f ∗(vivi+1) = 2n− 1 + 4i, for 1 ≤ i ≤⌊n2
⌋,
f ∗(vn+1−ivn−i) = 2n+ 4i, for 1 ≤ i ≤⌊n2
⌋− 1,
f ∗(viv′i) =
f(vi) 1 ≤ i ≤⌊n2
⌋− 1 and i is odd
f(vi)− 2⌊n2
⌋+ 1 ≤ i ≤ n and i is odd
f(vi)− 2 1 ≤ i ≤⌊n2
⌋and i is even
f(vi)⌊n2
⌋+ 2 ≤ i ≤ n and i is even
and
f ∗(ui+1vi) = 2n, for i =⌊n2
⌋.
Case (ii) n ≡ 1(mod 4).We define f : V (G⊙K1) → {1, 2, 3, . . . , 4n} as follows:
f(ui) = 2i, for 1 ≤ i ≤ n, f(u′i) = 2i− 1, for 1 ≤ i ≤ n,
f(vi) =
{2n− 3 + 4i 1 ≤ i ≤
⌊n2
⌋+ 1 and i is odd
2n− 1 + 4i 1 ≤ i ≤⌊n2
⌋and i is even,
f(vn+1 − i) =
{2n− 2 + 4i 1 ≤ i ≤
⌊n2
⌋and i is odd
2n + 4i 1 ≤ i ≤⌊n2
⌋and i is even
and
f(v′i) =
f(vi) + 2 1 ≤ i ≤⌊n2
⌋and i is odd
f(vi) + 1 i =⌊n2
⌋+ 1 and i is odd
f(vi) + 2⌊n2
⌋+ 3 ≤ i ≤ n and i is odd
f(vi)− 2 1 ≤ i ≤ n and i is even.
The induced edge labeling is as follows:
f ∗(uiui+1) = 2i, for 1 ≤ i ≤ n− 1,
f ∗(uiu′i) = 2i− 1, for 1 ≤ i ≤ n,
f ∗(vivi+1) = 2n− 1 + 4i, for 1 ≤ i ≤⌊n2
⌋,
f ∗(vn+1−ivn−i) = 2n+ 4i, for 1 ≤ i ≤⌊n2
⌋,
F -GEOMETRIC MEAN LABELING OF SOME CHAIN GRAPHS AND THORN GRAPHS 179
f ∗(viv′i) =
{f(vi) 1 ≤ i ≤ n and i is oddf(vi)− 2 1 ≤ i ≤ n and i is even
and
f ∗(uivi) = 2n, for i =⌊n2
⌋+ 1.
Case (iii) n ≡ 2(mod 4).We define f : V (G⊙K1) → {1, 2, 3, . . . , 4n} as follows:
f(ui) =
{2i 1 ≤ i ≤ n and i is odd2i− 1 1 ≤ i ≤ n and i is even,
f(u′i) =
{2i− 1 1 ≤ i ≤ n and i is odd2i 1 ≤ i ≤ n and i is even,
f(vi) =
{2n− 1 + 4i 1 ≤ i ≤
⌊n2
⌋and i is odd
2n− 3 + 4i 1 ≤ i ≤⌊n2
⌋− 1 and i is even,
f(vn+1−i) =
{2n+ 4i 1 ≤ i ≤
⌊n2
⌋and i is odd
2n− 2 + 4i 1 ≤ i ≤⌊n2
⌋− 1 and i is even,
and
f(v′i) =
f(vi)− 2 1 ≤ i ≤⌊n2
⌋and i is odd
f(vi) + 2⌊n2
⌋+ 2 ≤ i ≤ n and i is odd
f(vi) + 2 1 ≤ i ≤⌊n2
⌋− 1 and i is even
f(vi)− 2⌊n2
⌋+ 1 ≤ i ≤ n and i is even
The induced edge labeling is as follows:
f ∗(uiui+1) = 2i, for 1 ≤ i ≤ n− 1,
f ∗(uiu′i) = 2i− 1, for 1 ≤ i ≤ n,
f ∗(vivi+1) = 2n− 1 + 4i, for 1 ≤ i ≤⌊n2
⌋,
f ∗(vn+1−ivn−i) = 2n+ 4i, for 1 ≤ i ≤⌊n2
⌋− 1,
f ∗(viv′i) =
f(vi)− 2 1 ≤ i ≤⌊n2
⌋and i is odd
f(vi)⌊n2
⌋+ 2 ≤ i ≤ n and i is odd
f(vi) 1 ≤ i ≤⌊n2
⌋− 1 and i is even
f(vi)− 2⌊n2
⌋+ 1 ≤ i ≤ n and i is even
and
f ∗(ui+1vi) = 2n, for i =⌊n2
⌋+ 1.
180 A. DURAI BASKAR, S. AROCKIARAJ AND B. RAJENDRAN
Case (iv) n ≡ 3(mod 4).We define f : V (G⊙K1) → {1, 2, 3, . . . , 4n} as follows:
f(ui) = 2i, for 1 ≤ i ≤ n, f(u′i) = 2i− 1, for 1 ≤ i ≤ n,
f(vi) =
{2n− 1 + 4i 1 ≤ i ≤
⌊n2
⌋and i is odd
2n− 3 + 4i 1 ≤ i ≤⌊n2
⌋+ 1 and i is even,
f(vn+1−i) =
{2n+ 4i 1 ≤ i ≤
⌊n2
⌋and i is odd
2n− 2 + 4i 1 ≤ i ≤⌊n2
⌋and i is even,
and
f(v′i) =
f(vi)− 2 1 ≤ i ≤⌊n2
⌋and i is odd
f(vi) + 1 i =⌊n2
⌋+ 1 and i is odd
f(vi)− 2⌊n2
⌋+ 3 ≤ i ≤ n and i is odd
f(vi) + 2 1 ≤ i ≤ n and i is even.
The induced edge labeling is as follows:
f ∗(uiui+1) = 2i, for 1 ≤ i ≤ n− 1,
f ∗(uiu′i) = 2i− 1, for 1 ≤ i ≤ n,
f ∗(vivi+1) = 2n− 1 + 4i, for 1 ≤ i ≤⌊n2
⌋,
f ∗(vn+1−ivn−i) = 2n+ 4i, for 1 ≤ i ≤⌊n2
⌋,
f ∗(viv′i) =
{f(vi)− 2 1 ≤ i ≤ n and i is oddf(vi) + 2 1 ≤ i ≤ n and i is even
and
f ∗(uivi) = 2n, for i =⌊n2
⌋+ 1.
Hence, f is a F -Geometric mean labeling of G ⊙ K1. Thus the graph G ⊙ K1 is aF -Geometric mean graph. �
A F -Geometric mean labeling of G⊙K1 is as shown in Figure 11.
Theorem 2.8. For a H−graph G, G⊙ S2 is a F -Geometric mean graph.
Proof. Let u1, u2, . . . , un and v1, v2, . . . , vn be the vertices of G. Therefore,
V [G⊙ S2] = V (G) ∪ {u′i, u
′′i , v
′i, v
′′i ; 1 ≤ i ≤ n}
and
E[G⊙ S2] = E(G) ∪ {uiu′i, uiu
′′i , viv
′i, viv
′′i ; 1 ≤ i ≤ n}.
F -GEOMETRIC MEAN LABELING OF SOME CHAIN GRAPHS AND THORN GRAPHS 181
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Figure 11. A F -Geometric mean labeling of H graph G⊙K1
Case (i) n is odd.We define f : V (G⊙ S2) → {1, 2, 3, . . . , 6n} as follows:
f(ui) = 3i− 1, for 1 ≤ i ≤ n,
f(u′i) = 3i− 2, for 1 ≤ i ≤ n,
f(u′′i ) = 3i, for 1 ≤ i ≤ n,
f(vi) = 3n− 2 + 6i, for 1 ≤ i ≤⌊n2
⌋,
f(vn+1−i) = 3n− 3 + 6i, for 1 ≤ i ≤⌊n2
⌋+ 1,
f(v′i) =
f(vi)− 2 1 ≤ i ≤⌊n2
⌋
f(vi)− 1 i =⌊n2
⌋+ 1
f(vi) + 2⌊n2
⌋+ 2 ≤ i ≤ n
and
f(v′′i ) =
{f(vi) + 2 1 ≤ i ≤
⌊n2
⌋
f(vi)− 2⌊n2
⌋+ 1 ≤ i ≤ n.
The induced edge labeling is as follows:
f ∗(uiui+1) = 3i, for 1 ≤ i ≤ n− 1,
f ∗(uiu′i) = 3i− 2, for 1 ≤ i ≤ n,
f ∗(uiu′′i ) = 3i− 1, for 1 ≤ i ≤ n,
f ∗(uivi) = 3n, for i =⌊n2
⌋+ 1,
182 A. DURAI BASKAR, S. AROCKIARAJ AND B. RAJENDRAN
f ∗(vivi+1) = 3n+ 6i, for 1 ≤ i ≤⌊n2
⌋,
f ∗(vn+1−ivn−i) = 3n− 1 + 6i, for 1 ≤ i ≤⌊n2
⌋,
f ∗(viv′i) =
f(vi)− 2 1 ≤ i ≤⌊n2
⌋
f(vi)− 1 i =⌊n2
⌋+ 1
f(vi)⌊n2
⌋+ 2 ≤ i ≤ n
and
f ∗(viv′′i ) =
{f(vi) 1 ≤ i ≤
⌊n2
⌋
f(vi)− 2⌊n2
⌋+ 1 ≤ i ≤ n.
Case (ii) n is even.We define f : V (G⊙ S2) → {1, 2, 3, . . . , 6n} as follows:
f(ui) = 3i− 1, for 1 ≤ i ≤ n,
f(u′i) = 3i− 2, for 1 ≤ i ≤ n,
f(u′′i ) = 3i, for 1 ≤ i ≤ n− 1,
f(u′′n) = 3n+ 1,
f(vi) = 3n+ 1 + 6i, for 1 ≤ i ≤⌊n2
⌋− 1,
f(vn+1−i) = 3n+ 6(i− 1), for 2 ≤ i ≤⌊n2
⌋+ 1,
f(vn) = 3n+ 2,
f(v′i) =
{f(vi)− 2 1 ≤ i ≤
⌊n2
⌋
f(vi) + 2⌊n2
⌋+ 1 ≤ i ≤ n− 1,
f(v′n) = f(vn) + 1
and
f(v′′i ) =
f(vi) + 2 1 ≤ i ≤⌊n2
⌋− 1
f(vi)− 1 i =⌊n2
⌋
f(vi)− 2⌊n2
⌋+ 1 ≤ i ≤ n.
The induced edge labeling is as follows:
f ∗(uiui+1) = 3i, for 1 ≤ i ≤ n− 1,
f ∗(uiu′i) = 3i− 2, for 1 ≤ i ≤ n,
f ∗(uiu′′i ) = 3i− 1, for 1 ≤ i ≤ n,
f ∗(ui+1vi) = 3n + 1, for i =⌊n2
⌋,
f ∗(vivi+1) = 3n + 3 + 6i, for 1 ≤ i ≤⌊n2
⌋,
F -GEOMETRIC MEAN LABELING OF SOME CHAIN GRAPHS AND THORN GRAPHS 183
f ∗(vn+1−ivn−i) = 3n− 4 + 6i, for 2 ≤ i ≤⌊n2
⌋,
f ∗(vnvn−1) = 3n+ 3,
f ∗(viv′i) =
{f(vi)− 2 1 ≤ i ≤
⌊n2
⌋
f(vi)⌊n2
⌋+ 1 ≤ i ≤ n
and
f ∗(viv′′i ) =
f(vi) 1 ≤ i ≤⌊n2
⌋− 1
f(vi)− 1 i =⌊n2
⌋
f(vi)− 2⌊n2
⌋+ 1 ≤ i ≤ n.
Hence, f is a F -Geometric mean labeling of G ⊙ S2. Thus the graph G ⊙ S2 is aF -Geometric mean graph. �
A F -Geometric mean labeling of G⊙ S2 is as shown in Figure 12.
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41
39
35
33
29
rrr
r
r
r
22
2523
22 23 26
21 2726
27
2424
25
Figure 12. A F -Geometric mean labeling of H graph G⊙ S2
Theorem 2.9. Ln ⊙K1 is a F -Geometric mean graph, for n ≥ 2.
Proof. Let V (Ln) = {ui, vi; 1 ≤ i ≤ n} be the vertex set of the ladder Ln andE(Ln) = {uivi; 1 ≤ i ≤ n} ∪ {uiui+1, vivi+1; 1 ≤ i ≤ n − 1} be the edge set of theladder Ln. Let wi be the pendent vertex adjacent to ui, and xi be the pendent vertexadjacent to vi, for 1 ≤ i ≤ n.
184 A. DURAI BASKAR, S. AROCKIARAJ AND B. RAJENDRAN
We define f : V (Ln ⊙K1) → {1, 2, 3, . . . , 5n− 1} as follows:
f(u1) = 3,
f(v1) = 4,
f(x1) = 2,
f(ui) = 5i− 3, for 2 ≤ i ≤ n,
f(vi) = 5i− 2, for 2 ≤ i ≤ n,
f(wi) = 5i− 4, for 1 ≤ i ≤ n
and
f(xi) = 5i− 1, for 2 ≤ i ≤ n.
The induced edge labeling is as follows
f ∗(u1v1) = 3,
f ∗(v1x1) = 2,
f ∗(uivi) = 5i− 3, for 2 ≤ i ≤ n,
f ∗(wiui) = 5i− 4, for 1 ≤ i ≤ n,
f ∗(vixi) = 5i− 2, for 2 ≤ i ≤ n,
f ∗(uiui+1) = 5i− 1, for 1 ≤ i ≤ n− 1,
f ∗(vivi+1) = 5i, for 1 ≤ i ≤ n− 1.
Hence f is a F -Geometric mean labeling of Ln ⊙K1. Thus the graph Ln ⊙ K1 is aF -Geometric mean graph, for n ≥ 2. �
A F -Geometric mean labeling of L8 ⊙K1 is as shown in Figure 13.r r r r r r r r
r r r r r r r r
r r r r r r r r
r r r r r r r r
1
1
3
3
4
2
2
4
5
6
6
7
7
8
8
9
9
10
11
11
1214
12
1513
13
14
16
16
1719
17
2018
18
19
21
21
22 24
22
2523
23
24
26
26
27 29
27
3028
28
29
3131
3234
32
3533
33
34
3636
3737
38
38
39
Figure 13. A F -Geometric mean labeling of L8 ⊙K1
Theorem 2.10. Ln ⊙ S2 is a F -Geometric mean graph, for n ≥ 2.
Proof. Let V (Ln) = {ui, vi; 1 ≤ i ≤ n} be the vertex set of the ladder Ln andE(Ln) = {uivi; 1 ≤ i ≤ n} ∪ {uiui+1, vivi+1; 1 ≤ i ≤ n − 1} be the edge set of theladder Ln.
F -GEOMETRIC MEAN LABELING OF SOME CHAIN GRAPHS AND THORN GRAPHS 185
Let w(i)1 and w
(i)2 be the pendant vertices at each vertex ui, for 1 ≤ i ≤ n and x
(i)1
and x(i)2 be the pendant vertices at each vertex vi, for 1 ≤ i ≤ n. Therefore
V (Ln ⊙ S2) = V (Ln) ∪ {w(i)1 , w
(i)2 , x
(i)1 , x
(i)2 ; 1 ≤ i ≤ n}
and
E(Ln ⊙ S2) = E(Ln) ∪ {uiw(i)1 , uiw
(i)2 , vix
(i)1 , vix
(i)2 ; 1 ≤ i ≤ n}.
We define f : V (Ln ⊙ S2) → {1, 2, 3, . . . , 7n− 1} as follows :
f(ui) =
3 i = 17i− 2 2 ≤ i ≤ n and i is even7i− 5 3 ≤ i ≤ n and i is odd,
f(vi) =
5 i = 17i− 4 2 ≤ i ≤ n and i is even7i− 1 3 ≤ i ≤ n and i is odd,
f(w(i)1 ) =
{7i− 3 1 ≤ i ≤ n and i is even7i− 6 1 ≤ i ≤ n and i is odd,
f(w(i)2 ) =
2 i = 17i− 1 2 ≤ i ≤ n and i is even7i− 4 3 ≤ i ≤ n and i is odd,
f(x(i)1 ) =
{7i− 6 1 ≤ i ≤ n and i is even7i− 3 1 ≤ i ≤ n and i is odd,
f(x(i)2 ) =
6 i = 17i− 5 2 ≤ i ≤ n and i is even7i− 2 3 ≤ i ≤ n and i is odd.
The induced edge labeling is as follows:
f ∗(uiui+1) = 7i− 1, for 1 ≤ i ≤ n− 1,
f ∗(uivi) = 7i− 4, for 1 ≤ i ≤ n,
f ∗(vivi+1) = 7i, for 1 ≤ i ≤ n− 1,
f ∗(uiw(i)1 ) =
{7i− 3 1 ≤ i ≤ n and i is even7i− 6 1 ≤ i ≤ n and i is odd,
f ∗(uiw(i)2 ) =
{7i− 2 1 ≤ i ≤ n and i is even7i− 5 1 ≤ i ≤ n and i is odd,
f ∗(vix(i)1 ) =
{7i− 6 1 ≤ i ≤ n and i is even7i− 3 1 ≤ i ≤ n and i is odd,
and
f ∗(vix(i)2 ) =
{7i− 5 1 ≤ i ≤ n and i is even7i− 2 1 ≤ i ≤ n and i is odd.
186 A. DURAI BASKAR, S. AROCKIARAJ AND B. RAJENDRAN
Hence, f is a F -Geometric mean labeling of Ln ⊙ S2. Thus the graph Ln ⊙ S2 is aF -Geometric mean graph, for n ≥ 2. �
A F -Geometric mean labeling of L7 ⊙ S2 is as shown in Figure 14.
r r r r r r r
r r r r r r r
☞☞☞
✂✂✂
❏❏❏
r r r r r r r r r r r r r r
r r r r r r r r r r r r r r
1
1
3
3
5
4
4 6 8 9 18 19 22 23 32 33 36 37 46 47
2 11 13 15 17 25 27 29 31 39 41 43 45
2 11 12 15 16 25 26 30 39 40 43 44296 13 20 27 34 41
12 16 26 30 40 44
10 17 24 31 38 45
7 10 14 20 21 24 28 34 35 38 42 48
5 8 9 18 19 22 23 32 33 36 37 46 47
Figure 14. A F -Geometric mean labeling of L7 ⊙ S2
References
[1] A. Durai Baskar, S. Arockiaraj and B. Rajendran, Geometric Mean Graphs, (Communicated).[2] J. A. Gallian, A dynamic survey of graph labeling, The Electronic Journal of Combinatorics,
17(2011).[3] F. Harary, Graph theory, Addison Wesely, Reading Mass., 1972.[4] R. Ponraj and S. Somasundaram, Further results on mean graphs, Proceedings of Sacoeference,
(2005), 443–448.[5] A. Rosa, On certain valuation of the vertices of graph, International Symposium, Rome, July
1966, Gordon and Breach, N. Y. and Dunod Paris (1967), 349–355.[6] S. Somasundaram and R. Ponraj, Mean labeling of graphs, National Academy Science Letter,
26(2003), 210–213.[7] S. Somasundaram and R. Ponraj, Some results on mean graphs, Pure and Applied Mathematika
Sciences, 58(2003), 29–35.[8] S. Somasundaram, P. Vidhyarani and R. Ponraj, Geometric mean labeling of graphs, Bulletin
of Pure and Applied sciences, 30E (2011), 153–160[9] S. Somasundaram, P. Vidhyarani and S. S. Sandhya, Some results on Geometric mean graphs,
International Mathematical Form, 7 (2012), 1381–1391.[10] R. Vasuki and A. Nagarajan, Further results on mean graphs, Scientia Magna, 6(3) (2010),
1–14.
Department of Mathematics,Mepco Schlenk Engineering College,Mepco Engineering College (Po) - 626 005Sivakasi, Tamilnadu, INDIA.E-mail address : [email protected], sarockiaraj [email protected],