96
Minimum Dominating Extended Energy
M. R. Rajesh Kanna, S. RoopaAbstract : In this manuscript we defined a new type of matrix called minimum dominating extended matrix and hence energy by using degree of a adjacent vertices. In this manuscript we have calculated minimum dominating extended energies for some standard graphs. Latterly, the manuscript lower and upper bounds for this extended energy are also obtained.
Index Terms: Minimum dominating set, Extended matrix, Extended energy, Eigenvalues.
————————————————————
1.
INTRODUCITON
The perception of energy of a graph was led through I.
Gutman [3] during 1978. G is a graph containing vertices
and edges. Let (aij) is an adjacency matrix of a
graph. Eigenvalues 1,2,3,... of A, expected in
decreasing direction, be the eigenvalues of G. Energy of a
graph G is denoted by
G and is represented by
1
) (
i i
G .
For particulars on the mathematical features of the theory of graph energy observe the documents [4] along with references mentioned in that.
1.1 Extended Energy
Extended matrix of G is the matrix defined by
), ( : )
( ij
ex G a
A where
otherwise G E v v if d d
d d
a i j
i j j i ij
0
) ( 2
1
The eigenvalues of Aex(G) are called extended eigenvalues.
The extended energy [8] of G is described as
1 : ) (
i i ex G
E where 1,2,3,... are the
eigenvalues of Aex(G).
1.2 Minimum Dominating Extended (MDE) Energy:
MDE matrix of G is the matrix describedby ,
), ( : )
( ij
D
ex G x
A wherever
else or
D v j
i if
G E v v if d d d d
x i
j i
i j
j i
ij
0
& 1
) ( 2
1
Here D is Minimum dominating collection of vertices of G. MDE eigenvalues of the graph G are the eigenvalues of
) (G
AexD . If 1,2,3,... are the eigenvalues of the
matrix AexD(G) then MDE energy of G is demarcated as
1 : ) (
i i D
ex G
E .
Example 1: Probable minimum dominating collections for the
succeeding graph G [Figure 1] are
i) D1
v1,v5
ii) D2
v2,v5
iii) D3
v2,v6
FIGURE 1
i)
0 8 17 0 0 0 0
8 17 1 4 5 4 5 1 0
0 4 5 0 0 4 5 0
0 4 5 0 0 4 5 0
0 1 4 5 4 5 0 8 17
0 0 0 8 17 8 17 1
) (G AexD
Characteristic equation is
. 0 512 7225 4096
211921 32
421 32
489 2
2 3
4 5
6
Minimum dominating extended eigenvalues are ,
————————————————
Dr. Rajesh Kanna M.R., Sri D.D. Urs GFGC, Hunasuru – 571105, Mysuru Dist., India. PH-9448150508. E-mail:
Roopa S., Sri D.D. Urs GFGC, Hunasuru – 571105, Mysuru Dist., India, and Research Scholar, Career Point University, Kota, Rajasthan, India. PH-9448617973. E-mail:
8317842. 4.23733123
6256991, 2.26474223
1822621, 2.56552006
1509463, 2.19739302
87572508, 0.26083960
0.0,
6
5 4
3 2
1
Minimum dominating extended energy,
ED1(G)11.7866657 7542142.
ex
ii)
0 8 17 0 0 0 0
8 17 1 4 5 4 5 1 0
0 4 5 0 0 4 5 0
0 4 5 0 0 4 5 0
0 1 4 5 4 5 1 8 17
0 0 0 0 8 17 0
) (G AexD
Characteristic equation is
. 0 4096
199121 32
289 32
489 2
2 3
4 5
6
Minimum dominating extended eigenvalues are
350306. 4.43010568
350306, 2.43010568
0000001, 2.12500000
2.125,
0.0, 0.0,
6 5
4 3
2 1
Minimum dominating extended energy, 6700612.
11.1102113 )
(
2 G
EexD
Minimum dominating extended energy is influenced by the dominating set.
2
Assets
of
Minimum
Dominating
Extended(MDE) Eigenvalues
Theorem - 2.1. If 1,2,3,...are the eigenvalues of
MDE matrix AexD(G) then
2
1 i
2
1 i
i
2 1
(ii) .
)
(
j
i i
j j i i
d d
d d D
D i
where D is the MDE set.
Proof :- (a) We see that the totality of the eigenvalues of
) (G
AexD is the trace of AexD(G).
1
i 1
i .
i
ii D
a
b) Correspondingly totality of squares of the eigenvalues of
) (G
AexD is the trace of
AexD(G)
2.
. 2
1 D
2 1 2 D
2
2 2 2
1 2 1
2 1
i 1 1
2 i
j
i i
j j i j
i i
j j i j i
ij i
ii
j i
ji ij i
ii i j
ji ij
d d d d
d d d
d a a
a a a
a a
3. Restrictions For Minimum Domination
Extended Energy
Parallel to McClelland’s [6] restriction for energy of a graph,
restriction for EexD(G)are specified in the succeeding
paragraph.
Theorem: ( 3.1) If D is Minimum dominating collection &
) ( det AexD G
then
. 2
1
) ( E ) 1 ( 2
1
2
D ex 2
2
j
i i
j
j i j
i i
j
j i
d d
d d D
G d
d
d d D
Proof: Cauchy Schwarz variation stands
j
i i
j
j i D
ex
j
i i
j
j i D
ex
i i i
i i i
i i
i i
i i
i i i
d d d d D
G E
d d d d D
G E
b a If
b a
b a
2 2
2 2
1 2
1 2
1 1
2
1 2 2
1
2 1 )
(
2.1] m [By theore 2
1 ]
) ( [
1 then
, 1
98
(3.1) . ) 1 (
) ( A det
) 1 (
1
2
j i
2 2 D ex 2
1
) 1 (
1 1) -2(
1
) 1 (
1
j j
j i
i i i
i j i
i
j i
i
G
Now reflect,
2 2
2 2
2 D ex
j i 2
1 i
2
1 i 2
) 1 ( 2
1 )
( E ., ,
3.1] [From ) 1 ( 2
1 )]
( [E
]
) ( [
j
i i
j
j i D
ex
j
i i
j
j i j i n
i n
i D
ex
d d
d d D
G e i
d d
d d D
G G E
Theorem 3.2 If 1(G)is the biggest minimum dominating
extended eigenvalue of AexD(G), then
i j i
j
j i
d d
d d D
G
2
) (
1
.
Proof: LetY be some nonzero vector. Then by [1], we have
Y Y
AY Y A
Y '
'
0
1( ) max
i j i
j
j i
d d d d D
J J
AJ J A
2 )
(
' '
1 Where J
remains a unit matrix [1,1,1,..., 1]'.
Alike to Koolen and Moulton’s [5] upper bound for energy of a
graph, higher bound for EexD(G)is specified in next theorem.
Theorem 3.3 If
. 2
2
) 1 (
2
) ( E then 2
2
2 D ex
j
i i
j
j i
j
i i
j
j i
j
i i
j
j i
j
i i
j
j i
d d
d d D
d d
d d D
d d
d d D
G d
d
d d D
Proof. Cauchy-Schwartz variation stands
j
i i
j
j i j
i i
j
j i
j
i i
j
j i j
i i
j
j i D
ex
j
i i
j
j i D
ex
i i i
i i i
i i
i i i
i i
i i
d d
d d D
x
x d d
d d D
x x f f untion decreasig
For
x d d
d d D
x x f Let
d d
d d D
G E
d d
d d D
G E
b a Put
b a
b a
2
2 2 '
2 2
2 1 2
1
2 1 2 2
1
2 2
2 2
2 2
2
2 2 2
2
2 1
0
2 1 )
1 (
) 1 ( 1
0 ) (
2 1 )
1 ( ) (
2 1 )
1 ( )
(
2
1 )
1 ( ] ) ( [
1 then
, 1
. 2
2 1 )
1 (
2
) (
2
) ( . , .
2 )
( ) ( . , .
2
) (
] 2 . 3 [
2 2
have w e , 2
D
2 2
1 1
1
j i
j
i i
j j i i
j j i j
i i
j j i D
e x
j
i i
j j i D
e x
j
i i
j j i D
e x
j
i i
j j i
j
i i
j j i j
i i
j j i j
i i
j j i
d d
d d D
d d
d d D
d d
d d D
G E
d d
d d D
f G E e i
d d
d d D
f f
G E e i
d d
d d D
f f
theorem F rom
d d
d d D
d d
d d D
d d
d d Since
Milovanovic [7] bounds for MDE energy is proved below.
Theorem (3.4) Let 1 2 . . . be a decreasing
directive of minimum dominating extended eigenvalues of
) (G
2 1 2) ( 2
1 )
( n
j
i i
j
j i D
ex
d d d d D
G
E
Wherever
2 1 1 2 )
(
in addition
x denotesintegral portion of a real number.
Proof: Let r,r1,r2,..., r,R and s,s1,s2,..., s,S be real
quantities such that r ri R and s si S i1, 2,...,
Then the subsequent variation is effective.
) ( ) ( ) (
1 1 1
s S r R s
r s r
i i i
i i i
i
where
2 1 1 2 )
(
and equivalence clutches if and
only if r1 r2 ... r and s1 s2 ... s. If
,
,
, 1
s r s and R S
ri i i i then
21 2
1 1
2
)
(
i
i i
i
However
2
1 2
2 1
i i j i
j
j i i
d d d d
D and
2
2 1 ) (
j
i i
j j i D
ex
d d
d d D
G
E
then the overhead variation turn out to be
21 2
2 1
2 2
) ( 2
1 ) ( ., .
) ( ) ( 2
1
j
i i
j
j i D
ex
D
ex j
i i
j
j i
d d d d D
G E e i
G E d
d d d D
Theorem 3.5. Let 1 2 . . . 0 remain a
decreasing direction of eigenvalues of AexD(G) then
2
1 ) (
1
1 2
j
i i
j
j i
D
ex
d d d d D
G
E .
Proof: Let fi 0, gi, h and H stand actual numbers
nourishing hfi gi Hfi ,then the succeeding variation
grips. [Theorem 2, [7] ]
2
1
) (
) (
2
1 ., .
1
, 1 ,
1
1 2
1 1
2
1 1
1 1 1
2
1
1 1
1 2
j
i i
j
j i
D ex
D ex j
i i
j
j i
i i i
i i
i i i
i i
i i i
i i
d d
d d D
G E
G E d
d
d d D
e i
then H
and h
f g
Put
g f H h f hH g
Bepat and S. Pati [2] demonstrated that if the graph energy is a rational number then it is an even integer. Comparable outcome for MDE energy is specified in the ensuing deduction.
Theorem 3.6. If the minimum dominating extended energy
) (G EexD
is rational, then EexD(G) D (mod 2).
Proof: The evidence is like the deduction 5.4 of [9]
4 Minimum Dominating Extended Energy of a
few typical graphs
Theorem: (4.1) For 2 MDE energy of K is
. 5 2 )
2
( 2
Proof: K is a complete graph with vertex collection
v v v
V 1, 2,..., . Minimum dominating collection is
v1D .
MDE adjacency matrix is
0 1
1 1 1 2 1 1 1 1 1 2 1 1 1 1 1 2 1
1 1
1 1
2 1 0
1 1
1 1
2 1
1 1
1 1
2 1
1 1
1 1
2 1
1 1
1 1
2 1 0 1
1
1 1
2 1
1 1 1 1 2 1 1 1 1 1 2 1 1 1 1 1 2 1 1
) (
K AexD
Characteristic equation is
1 1
2
2
1
1
0.MDE spectrum is,
1 1
2
2
5 2 )
1 (
2
5 2 )
1 ( 1 ) (
2 2
K Spec ExtD
100
2 2 5.
2 5 2 1 2 5 2 1 ) 2 ( 1 2 2 2
K
D Ext
Theorem 4.2. MDE energy of K 2 , for 2 is
. 9 4 4 ) 3 2
( 2
Proof: Let the vertices of K 2 be
,
.1 i i n i v u V
Minimum dominating collection D
u1,v1
. Then
) (K 2 AexD
0 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 | 0 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 | | | 2 2 2 2 2 2 2 2 2 1 0 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 | 2 2 2 2 2 2 2 2 2 1 0 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 | 3 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 0 2 2 2 2 2 2 2 2 2 1 | 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 0 2 2 2 2 2 2 2 2 2 1 | 2 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 1 | 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 0 | 1 | 0 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 | 0 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 | | | 2 2 2 2 2 2 2 2 2 1 0 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 | 2 2 2 2 2 2 2 2 2 1 0 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 | 3 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 0 2 2 2 2 2 2 2 2 2 1 | 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 0 2 2 2 2 2 2 2 2 2 1 | 2 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 0 | 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 1 | 1 | 3 2 1 | 3 2 1 | n n n n
Characteristic equation is
. 0 ] 2 ) 3 2 ( [ ) 2 )( 1
( ( 2) 2
) 1 (
The MDE Spectrum is
1 1 2 1 1 2 9 4 4 ) 3 2 ( 2 9 4 4 ) 3 2 ( 2 0 1 ) ( 2 2 2 K SpecexD
MDE energy is
. 9 4 4 ) 3 2 ( 9 4 4 ) 2 ( 2 1 2 9 4 4 ) 3 2 ( 2 9 4 4 ) 3 2 ( ) 2 ( 2 ) 1 ( 0 1 ) ( 2 2 2 2 2
K D ex
Theorem: (4.3) For 2, MDE energy of K1,1 is
identical to .
1
3 10 15
12
5 4 3 2
5
Proof: Consider the Star graph K1, 1with vertex collection
0, 1, 2,..., 1
. v v v v
V MD collection is D
v0 . ThenMDE adjacency matrix is
)
(K1, 1 AexD
0 0 0 1 1 1 1 2 1 0 0 0 1 1 1 1 2 1 0 0 0 1 1 1 1 2 1 1 1 1 1 2 1 1 1 1 1 2 1 1 1 1 1 2 1 1
Characteristic equation is
. 0 ) 1 ( 4 ] 1 1 ) 1 ( 4 ) 1 ( 4 [ 2 2 2 2 MDE spectrum is
1 1 2 2 2 3 10 15 12 5 1 2 2 3 10 15 12 5 1 0 ) ( 2 3 4 5 2 3 4 5 1 , 1 K SpecD ex
MDE energy of K1, 1 is
. 1 3 10 15 12 5 2 2 3 10 15 12 5 2 2 2 3 10 15 12 5 ) 1 ( 2 2 3 10 15 12 5 ) 1 ( ) 2 ( 0 ) ( 2 3 4 5 2 3 4 5 2 3 4 5 2 3 4 5 1 , 1 K
D ex
Theorem 4.4. For 2, MDE energy of Crown graph S20
is identical to (2 4) 2 2 5 2 2 3.
Proof:- Let the vertices of Crown graph 0
2
S be
u1,u2,..., u ,v1,v2,..., v
, minimum dominating collectionis S
u1,v1
. Then
) (S20 AexD
) 2 2 ( 0 0 0 0 | 0 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 | | | 0 0 0 0 | 2 2 2 2 2 2 2 2 2 1 0 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 | 3 0 0 0 0 | 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 0 2 2 2 2 2 2 2 2 2 1 | 2 0 0 0 2 2 2 2 2 2 2 2 2 1 | 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 0 | 1 | 0 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 | 0 0 0 0 | | | 2 2 2 2 2 2 2 2 2 1 0 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 | 0 0 0 0 | 3 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 0 2 2 2 2 2 2 2 2 2 1 | 0 0 0 0 | 2 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 0 | 0 0 0 2 2 2 2 2 2 2 2 2 1 | 1 | 3 2 1 | 3 2 1 | n v v v v n u u u u n v v v v n u u u u
Characteristic equation is
1
2 1
2
2 ( 1) 1
2 ( 3) (2 3)
0MDE spectrum is
1 1 1 1 2 2 2 3 2 ) 3 ( 2 3 2 ) 3 ( 2 5 2 1 2 5 2 1 1 1 2 2 2 2
MDE energy is
. 3 2 5 2 ) 2 ( 2 2 3 2 ) 3 ( 2 3 2 ) 3 ( 2 5 2 ) 1 ( 2 5 2 ) 1 ( ) 2 ( 1 ) 2 ( 1 ) ( 2 2 2 2 2 2 0 2 S
D ex
Theorem 4.5. For 2, the minimum extended energy of
Windmill graph W is
. ) 1 ( ) 9 6 ( ) 2 2 ( ) 1 ( 2 4 2 2 2 3 5
Proof: Contemplate the Windmill graph W with vertex
collection V
v0,v1,v2,..., v1
. MD collection is
v0 .D Then MDE adjacency matrix is
) (W AexD
0 1 1 0 0 0 0 0 0 0 0 0 ) 1 ( 1 1 ) 1 ( 2 1 1 0 1 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 0 0 0 0 0 0 0 0 1 0 1 ) 1 ( 1 1 ) 1 ( 2 1 0 0 0 0 0 0 0 0 1 1 0 ) 1 ( 1 1 ) 1 ( 2 1 ) 1 ( 1 1 ) 1 ( 2 1 0 ) 1 ( 1 1 ) 1 ( 2 1 ) 1 ( 1 1 ) 1 ( 2 1 1 ) 1 ( 1 ) 1 )( 1 ( ) 1 )( 1 ( 2 2 1 1 2 1 0 ) 1 ( 1 2 2 1 1 2 1 0 v v v v v v v v v v v v v v v v v v v
v T T
Case(i):
If ‘m’ is odd then characteristic polynomial is
] 1 2 3 ) 8 8 2 ( ) 2 3 ( 1 2 3 ) 4 6 2 ( ) 2 ( 2 [ ) 1 ( )] 2 ( [ ) 1 ( 2 2 2 2 4 2 2 2 ) 2 ( 1 x x x x
MDE spectrum is
1 1 ) 2 ( 1 ) 1 ( ) 9 6 ( ) 2 2 ( ) 1 ( ) 1 ( ) 1 ( ) 9 6 ( ) 2 2 ( ) 1 ( ) 1 ( 1 2 ) ( 2 2 3 5 2 2 3 5 W Spec exD
MDE energy . ) 1 ( ) 9 6 ( ) 2 2 ( ) 1 ( 2 4 2 2 ) 1 ( ) 9 6 ( ) 2 2 ( ) 1 ( ) 1 ( 2 ) 1 ( ) 9 6 ( ) 2 2 ( ) 1 ( ) 1 ( ) 2 ( 1 ) 1 ( 2 ) ( 2 2 3 5 2 2 3 5 2 2 3 5 W ED ex
If ‘m’ is even then Characteristic polynomial is
] 1 2 3 ) 8 8 2 ( ) 2 3 ( 1 2 3 ) 4 6 2 ( ) 2 ( 2 [ ) 1 ( )] 2 ( [ ) 1 ( 2 2 2 2 4 2 2 2 ) 2 ( 1 1 x x x x
Then energy is
. ) 1 ( ) 9 6 ( ) 2 2 ( ) 1 ( 2 4 2 2 ) 1 ( ) 9 6 ( ) 2 2 ( ) 1 ( ) 1 ( 2 ) 1 ( ) 9 6 ( ) 2 2 ( ) 1 ( ) 1 ( ) 2 ( 1 ) 1 ( 2 ) ( 2 2 3 5 2 2 3 5 2 2 3 5 W EexD
Theorem 4.6. For , the minimum dominating energy
of Bipartite graph K, is
. 2
) 1
( 5 3 3 2 2 5
Proof. Vertex collection of K, ,( )be
u1,u2,..., u ,v1,v2,..., v
.The MDE adjacency matrix is AexD(K, )
0 0 0 0 0 2 1 2 1 2 1 2 1 0 0 0 0 2 1 2 1 2 1 2 1 0 0 0 0 2 1 2 1 2 1 2 1 0 0 0 0 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 1 0 0 0 2 1 2 1 2 1 2 1 0 1 0 0 2 1 2 1 2 1 2 1 0 0 1 0 2 1 2 1 2 1 2 1 0 0 0 1 2 1 3 2 1 3 2 1 3 2 1 n m m n u u u u v v v v u u u u v v v v n
Characteristic polynomial is
4 ] ) ( 4 4 [ ) 1 ( ) 1( x 1x 1 x2 x 2 2 2
Characteristic equation is
. 0 4 ] ) ( 4 4 [ ) 1 ( ) 1
( 1 1 2 2 2 2
x x x x
102
1 1
) 1 ( ) 1 (
2 2
2 2 0
1 ) (
5 2 2 3 3 5 5
2 2 3 3 5
,
k spec
MDE energy is,
. 2
) 1 (
2 2
2 2 )
1 ( 0 ) 1 ( 1 ) (
5 2 2 3 3 5
5 2 2 3 3 5
5 2 2 3 3 5
,
K EexD
CONCLUSIONS
In this article we defined Minimum dominating extended energy of a graph and established upper and lower bounds. This energy was computed for few typical graphs.
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