Let G=(V,E) be a graph with p vertices and q edges. Let f:V?{1,2,"¦q+1} is called an Integral Root labeling if it is possible to label all the vertices v?V with distinct elements from {1,2,"¦q+1} such that it induces an edge labeling f^+:E?{1,2,"¦q} defined as f^+ (uv)=?v((?(f(u))?^2+?(f(v))?^2+f(u)f(v))3)? is distinct for all uv?E. (i.e.) The distinct vertex labeling induces a distinct edge labeling on the graph. The graph which admits Integral Root labeling is called an Integral Root Graph. In this paper, we investigate the Integral Root labeling of P_m?G graphs likeP_m?P_n,P_m?(P_n ?K_1), P_m?L_n,P_m?(P_n ?K_1,2), P_m?(P_n ?K_1,3), P_m?(P_n ?K_1)?K_1,2 V. L. Stella Arputha Mary | N. Nanthini"Integral Root Labeling of Pm ∪ G Graphs" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-5 , August 2018, URL: http://www.ijtsrd.com/papers/ijtsrd18233.pdf http://www.ijtsrd.com/mathemetics/other/18233/integral-root-labeling-of-pm-∪-g-graphs/v-l-stella-arputha-mary
1. @ IJTSRD | Available Online @ www.ijtsrd.com
ISSN No: 2456
International
Research
Integral Root Labeling o
V. L. Stella Arputha Mary
1
Department of Mathematics,
St. Mary’s College (Autonomous), Thoothukudi
ABSTRACT
Let ܩ ൌ ሺܸ, ܧሻ be a graph with vertices and
labeling if it is possible to label all the vertices
induces an edge labeling ݂ା
: ܧ → ሼ1,2, …
݂ା
ሺݒݑሻ ൌ ቜට
ሺሺ௨ሻሻమାሺሺ௩ሻሻమାሺ௨ሻሺ௩ሻ
ଷ
ቝ is distinct for all
distinct edge labeling on the graph. The graph which
Graph.
In this paper, we investigate the Integral Root labeling of
ܮ,ܲ ∪ ሺܲʘܭଵ,ଶሻ, ܲ ∪ ሺܲʘܭଵ,ଷሻ, ܲ
Key words: P_m∪P_n, P_m∪(P_n ʘK_1), P_m
ʘK_1), P_m∪(P_n ʘK_1)ʘK_1,2
INTRODUCTION
The graph considered here will be finite, undirected and simple. The vertex set is denoted by
edge set is denoted byܧሺܩሻ. For all detailed survey of gr
terminology and notations we follow Haray [
concept of Integral Root Labeling of graphs in [8]. In this paper we investigate Integral Root la
ܲ ∪ ܩgraphs. The definitions and other informations which are useful for the present investigation are given
below.
BASIC DEFINITIONS
Definition: 3.1
A walk in which ݑଵ, ݑଶ, … ݑ are distinct is called a
Definition: 3.2
The graph obtained by joining a single pendent edge to each vertex of a path is called a
Definition: 3.3
The Cartesian product of two graphs ܩ
vertices ݑ(=ݑ1ݑ2) and ݒ(=ݒ1ݒ2) are adjacent in
is adjacent to ݒ1) .It is denoted by ܩ1×ܩ2
Definition: 3.4
The Corona of two graphs ܩ1 and ܩ2 is the graph
of ܩ2 where the ith
vertex of ܩ1 is adjacent to every vertex in the
@ IJTSRD | Available Online @ www.ijtsrd.com | Volume – 2 | Issue – 5 | Jul-Aug 2018
ISSN No: 2456 - 6470 | www.ijtsrd.com | Volume
International Journal of Trend in Scientific
Research and Development (IJTSRD)
International Open Access Journal
Integral Root Labeling of Pm∪∪∪∪G Graphs
V. L. Stella Arputha Mary1
, N. Nanthini2
Department of Mathematics, 2
M.phil Scholar
St. Mary’s College (Autonomous), Thoothukudi, Tamil Nadu, India
vertices and ݍedges. Let ݂: ܸ → ሼ1,2, … ݍ 1ሽ is called an
if it is possible to label all the vertices ݒ ∈ ܸ with distinct elements from ሼ1
ሼ … ݍሽ defined as
ቝ is distinct for all ݒݑ ∈ ( .ܧi.e.) The distinct vertex labeling induces a
distinct edge labeling on the graph. The graph which admits Integral Root labeling is called an
stigate the Integral Root labeling of ܲ ∪ ܩgraphs likeܲ ∪
∪ ሺܲʘܭଵሻʘܭଵ,ଶ
K_1), P_m∪L_n, P_m∪(P_n ʘK_1,2), P_m∪(P_n
The graph considered here will be finite, undirected and simple. The vertex set is denoted by
. For all detailed survey of graph labeling we refer to Gallian [1]. For all standard
we follow Haray [2]. V.L Stella Arputha Mary and N.Nanthini introduced the
concept of Integral Root Labeling of graphs in [8]. In this paper we investigate Integral Root la
graphs. The definitions and other informations which are useful for the present investigation are given
are distinct is called a Path. A path on ݊ vertices is denoted by
The graph obtained by joining a single pendent edge to each vertex of a path is called a
ܩ1=(ܸ1,ܧ1) and ܩ2=(ܸ2,ܧ2) is a graph )ܧ,ܸ(=ܩ with
) are adjacent in ܩ1×ܩ2 whenever (ݑ1=ݒ1and ݑ2 is adjacent to
2.
is the graph ܩ=ܩ1⨀ܩ2 formed by taking one copy of
is adjacent to every vertex in the ith
copy of ܩ2.
Aug 2018 Page: 2141
com | Volume - 2 | Issue – 5
Scientific
(IJTSRD)
International Open Access Journal
G Graphs
India
ሽ is called an Integral Root
ሼ1,2, … ݍ 1ሽ such that it
(i.e.) The distinct vertex labeling induces a
admits Integral Root labeling is called an Integral Root
ܲ,ܲ ∪ ሺܲʘܭଵሻ, ܲ ∪
(P_n ʘK_1,3), P_m∪(T_n
The graph considered here will be finite, undirected and simple. The vertex set is denoted by ܸሺܩሻ and the
aph labeling we refer to Gallian [1]. For all standard
2]. V.L Stella Arputha Mary and N.Nanthini introduced the
concept of Integral Root Labeling of graphs in [8]. In this paper we investigate Integral Root labeling of
graphs. The definitions and other informations which are useful for the present investigation are given
oted by ܲ
The graph obtained by joining a single pendent edge to each vertex of a path is called a Comb.
) with ܸ=ܸ1×ܸ2 and two
is adjacent to ݒ2) or (ݑ2=ݒ2and ݑ1
rmed by taking one copy of ܩ1 and |(ܩ1)| copies
2. International Journal of Trend in Scientific Research and Development (IJTSRD) ISSN: 2456-6470
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Definition: 3.5
The product graph ܲଶ × ܲ is called a Ladder and it is denoted by ܮ
Definition: 3.6
The union of two graphs ܩଵ ൌ ሺܸଵ, ܧଵ) and ܩଶ = (ܸଶ, ܧଶ) is a graph ܩ = ܩଵ ∪ ܩଶ with vertex set ܸ = ܸଵ ∪ ܸଶ
and the edge set ܧ = ܧଵ ∪ ܧଶ.
Definition: 3.7
The graph ܲʘܭଵ,ଶ is obtained by attaching ܭଵ,ଶ to each vertex of ܲ.
Definition: 3.8
The graph ܲʘܭଵ,ଷ is obtained by attaching ܭଵ,ଷ to each vertex of ܲ.
Definition: 3.9
A graph that is not connected is disconnected. A graph ܩ is said to be disconnected if there exist two nodes in
ܩ such that no path in ܩ has those nodes as endpoints. A graph with just one vertex is connected. An edgeless
graph with two (or) more vertices is disconnected
MAIN RESULTS
Theorem: 4.1
ܲ ∪ ܲ is an Integral Root graph.
Proof:
Let ܲ = ݑଵ, ݑଶ, … . , ݑ be a path on ݉ vertices.
Let ܲ = ݒଵ, ݒଶ, … . , ݒ be another one path on ݊ vertices.
Let ܩ = ܲ ∪ ܲ.
Define a function ݂: ܸ()ܩ → {1,2, … , ݍ + 1} by
݂(ݑ) = ݅; 1 ≤ ݅ ≤ ݉;
݂(ݒ) = ݉ + ݅; 1 ≤ ݅ ≤ ݊.
Then we find the edge labels
݂ା(ݑݑାଵ) = ݅; 1 ≤ ݅ ≤ ݉ − 1;
݂ା(ݒݒାଵ) = ݉ + ݅; 1 ≤ ݅ ≤ ݊ − 1.
Then the edge labels are distinct.
Hence ܲ ∪ ܲ is a Integral Root graph.
Example: 4.2
An Integral Root labeling of ܲହ ∪ ܲ is show below.
Figure: 1
Theorem: 4.3
ܲ ∪ (ܲʘܭଵ) is a Integral Root graph.
3. International Journal of Trend in Scientific Research and Development (IJTSRD) ISSN: 2456-6470
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Proof:
Let ܲʘܭଵ be a Comb graph obtained from a path ܲ = ݒଵ, ݒଶ, … . , ݒ by joining a vertex ݑ to ݒ, 1 ≤ ݅ ≤ ݊.
Let ܲ = ݓଵ, ݓଶ, … , ݓ be a path.
Let ܩ = ܲ ∪ (ܲʘܭଵ).
Define a function ݂: ܸ()ܩ → {1,2, … . , ݍ + 1} by
݂(ݓ) = ݅; 1 ≤ ݅ ≤ ݉;
݂(ݒ) = ݉ + 2݅ − 1; 1 ≤ ݅ ≤ ݊;
݂(ݑ) = ݉ + 2݅; 1 ≤ ݅ ≤ ݊.
Then we find the edge labels are
݂ା(ݓݓାଵ) = ݅; 1 ≤ ݅ ≤ ݉ − 1;
݂ା(ݒݒାଵ) = ݉ + 2݅; 1 ≤ ݅ ≤ ݊ − 1;
݂ା(ݒݑ) = ݉ + 2݅ − 1; 1 ≤ ݅ ≤ ݊ − 1.
Then the edge labels are distinct.
Hence ܲ ∪ (ܲʘܭଵ) is an Integral Root graph.
Example: 4.4
An Integral Root labeling of ܲହ ∪ (ܲହʘܭଵ) is given below.
Figure: 2
Theorem: 4.5
ܲ ∪ ܮ is an Integral Root graph.
Proof:
Let ܲ = ݑଵ, ݑଶ, … . , ݑ be a path.
Let {ݒଵ, ݒଶ, … , ݒ , ݓଵ, ݓଶ, … . . , ݓ} be the vertices of ladder.
efine a function ݂: ܸ()ܩ → {1,2, … . , ݍ + 1} by
݂(ݑ) = ݅; 1 ≤ ݅ ≤ ݉;
݂(ݒ) = ݉ + 3݅ − 2; 1 ≤ ݅ ≤ ݊;
݂(ݓ) = ݉ + 3݅ − 1; 1 ≤ ݅ ≤ ݊.
4. International Journal of Trend in Scientific Research and Development (IJTSRD) ISSN: 2456-6470
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Then we find the edge labels
݂ା(ݑݑାଵ) = ݅; 1 ≤ ݅ ≤ ݉ − 1;
݂ା(ݒݒାଵ) = ݉ + 3݅ − 1; 1 ≤ ݅ ≤ ݊ − 1;
݂ା(ݓݓାଵ) = ݉ + 3݅; 1 ≤ ݅ ≤ ݊ − 1.
݂ା(ݒݓ) = ݉ + 3 − 2݅; 1 ≤ ݅ ≤ ݊.
Then the edge labels are distinct.
Hence ܲ ∪ ܮ is an Integral Root graph.
Example: 4.6
An Integral Root labeling of ܲହ ∪ ܮହ is displayed below.
Figure: 3
Theorem: 4.7
ܲ ∪ (ܲʘܭଵ,ଶ) is a Integral Root graph.
Proof:
Let ܲʘܭଵ,ଶ be a graph obtained by attaching each vertex of a path ܲ to the central vertex of ܭଵ,ଶ.
Let ܲ = ݒଵ, ݒଶ, … , ݒ be a path.
Let ݓ and ݔ be the vertices of ܭଵ,ଶ which are attaching with the vertex ݒ of ܲ
1 ≤ ݅ ≤ ݊ .
Let ܲ = ݑଵ, ݑଶ, … . , ݑ be a path.
Let ܩ = ܲ ∪ (ܲʘܭଵ,ଶ).
Define a function ݂: ܸ()ܩ → {1,2, … . , ݍ + 1} by
݂(ݑ) = ݅; 1 ≤ ݅ ≤ ݉;
݂(ݒ) = ݉ + 3݅ − 1; 1 ≤ ݅ ≤ ݊;
݂(ݓ) = ݉ + 3݅ − 2; 1 ≤ ݅ ≤ ݊;
݂(ݔ) = ݉ + 3݅; 1 ≤ ݅ ≤ ݊.
5. International Journal of Trend in Scientific Research and Development (IJTSRD) ISSN: 2456-6470
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Then we find the edge labels are
݂ା(ݑݑାଵ) = ݅; 1 ≤ ݅ ≤ ݉ − 1;
݂ା(ݒݒାଵ) = ݉ + 3݅; 1 ≤ ݅ ≤ ݊ − 1;
݂ା(ݒݓ) = ݉ + 3݅ − 2; 1 ≤ ݅ ≤ ݊;
݂ା(ݔݒ) = ݉ + 3݅ − 1; 1 ≤ ݅ ≤ ݊.
Hence ܲ ∪ (ܲʘܭଵ,ଶ) is a Integral Root graph.
Example: 4.8
An Integral Root labeling of ܲହ ∪ (ܲଷʘܭଵ,ଶ) is given below.
Figure: 4
Theorem: 4.9
ܲ ∪ (ܲʘܭଵ,ଷ) is a Integral Root graph.
Proof:
Let ܲʘܭଵ,ଶ be a graph obtained by attaching each vertex of a path ܲ to the central vertex of ܭଵ,ଷ.
Let ܲ = ݓଵ, ݓଶ, … , ݓ be a path.
Let ݒ, ݔ and ݕ be the vertices of ܭଵ,ଷ which are attaching with the vertex ݓ of ܲ
1 ≤ ݅ ≤ ݊ .
Let ܲ = ݑଵ, ݑଶ, … . , ݑ be a path.
Let ܩ = ܲ ∪ (ܲʘܭଵ,ଷ).
Define a function ݂: ܸ()ܩ → {1,2, … . , ݍ + 1} by
݂(ݑ) = ݅; 1 ≤ ݅ ≤ ݉;
݂(ݒ) = ݉ + 4݅ − 3; 1 ≤ ݅ ≤ ݊;
݂(ݓ) = ݉ + 4݅ − 2; 1 ≤ ݅ ≤ ݊;
݂(ݔ) = ݉ + 4݅ − 1; 1 ≤ ݅ ≤ ݊;
݂(ݕ) = ݉ + 4݅; 1 ≤ ݅ ≤ ݊.
Then we find the edge labels are
݂ା(ݑݑାଵ) = ݅; 1 ≤ ݅ ≤ ݉ − 1;
݂ା(ݓݓାଵ) = ݉ + 4݅; 1 ≤ ݅ ≤ ݊ − 1;
݂ା(ݒݓ) = ݉ + 4݅ − 3; 1 ≤ ݅ ≤ ݊;
݂ା(ݔݓ) = ݉ + 4݅ − 2; 1 ≤ ݅ ≤ ݊;
݂ା(ݕݓ) = ݉ + 4݅ − 1; 1 ≤ ݅ ≤ ݊.
Then the edge labels are distinct.
Hence ܲ ∪ (ܲʘܭଵ,ଷ) is a Integral Root graph.
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Example: 4.10
An Integral Root labeling of ܲହ ∪ (ܲଷʘܭଵ,ଷ) is given below.
Figure: 5
Theorem: 4.11
ܲ ∪ (ܲʘܭଵ)ʘܭଵ,ଶ is a Integral root graph.
Proof:
Let ܩ = ܲ ∪ (ܲʘܭଵ)ʘܭଵ,ଶ.
Let ܲ = ݑଵ, ݑଶ, … . , ݑ be a path.
Let ܩଶ be a comb and ܩଵ be the obtained by attaching ܭଵ,ଶ at each pendant vertex of ܩଶ.
Let its vertices be ݒ, ݓ, ݔ, ݕ 1 ≤ ݅ ≤ ݊.
Define a function ݂: ܸ()ܩ → {1,2, … . , ݍ + 1} by
݂(ݑ) = ݅; 1 ≤ ݅ ≤ ݉;
݂(ݒ) = ݉ + 5݅ − 3; 1 ≤ ݅ ≤ ݊;
݂൫ݓ.
൯ = ݉ + 5݅ − 4; 1 ≤ ݅ ≤ ݊;
݂(ݔ) = ݉ + 5݅ − 2; 1 ≤ ݅ ≤ ݊;
݂(ݕ) = ݉ + 5݅; 1 ≤ ݅ ≤ ݊.
Then we find edge labels are
݂ା(ݑାଵݑ) = ݅; 1 ≤ ݅ ≤ ݉ − 1;
݂ା(ݒାଵݒ) = ݉ + 5݅ − 1; 1 ≤ ݅ ≤ ݊ − 1;
݂ା(ݒݓ) = ݉ + 5݅ − 4; 1 ≤ ݅ ≤ ݊;
݂ା(ݓݔ) = ݉ + 5݅ − 3; 1 ≤ ݅ ≤ ݊;
݂ା(ݓݕ) = ݉ + 5݅ − 2; 1 ≤ ݅ ≤ ݊.
Then the edge labels are distinct.
Hence ܲ ∪ (ܲʘܭଵ)ʘܭଵ,ଶ is an Integral Root graph.
Example: 4.12
An Integral Root labeling of ܲହ ∪ (ܲସʘܭଵ)ʘܭଵ,ଶ is given below.
7. International Journal of Trend in Scientific Research and Development (IJTSRD) ISSN: 2456-6470
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Figure: 6
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