7
Research Article New Results on the (Super) Edge-Magic Deficiency of Chain Graphs Ngurah Anak Agung Gede 1 and Adiwijaya 2 1 Department of Civil Engineering, Universitas Merdeka Malang, Jl. Taman Agung No. 1, Malang 65146, Indonesia 2 School of Computing, Telkom University, Jl. Telekomunikasi No. 1, Bandung 40257, Indonesia Correspondence should be addressed to Adiwijaya; [email protected] Received 3 February 2017; Accepted 29 May 2017; Published 12 July 2017 Academic Editor: Dalibor Froncek Copyright © 2017 Ngurah Anak Agung Gede and Adiwijaya. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Let be a graph of order V and size . An edge-magic labeling of is a bijection : () ∪ () → {1, 2, 3, . . . , V + } such that () + () + () is a constant for every edge ∈ (). An edge-magic labeling of with (()) = {1, 2, 3, . . . , V} is called a super edge-magic labeling. Furthermore, the edge-magic deficiency of a graph , (), is defined as the smallest nonnegative integer such that 1 has an edge-magic labeling. Similarly, the super edge-magic deficiency of a graph , (), is either the smallest nonnegative integer such that 1 has a super edge-magic labeling or +∞ if there exists no such integer . In this paper, we investigate the (super) edge-magic deficiency of chain graphs. Referring to these, we propose some open problems. 1. Introduction Let be a finite and simple graph, where () and () are its vertex set and edge set, respectively. Let V = |()| and = |()| be the number of the vertices and edges, respectively. In [1], Kotzig and Rosa introduced the concepts of edge-magic labeling and edge-magic graph as follows: an edge-magic labeling of a graph is a bijection : () ∪ () → {1, 2, 3, . . . , V + } such that () + () + () is a constant, called the magic constant of , for every edge of . A graph that admits an edge-magic labeling is called an edge-magic graph.A super edge-magic labeling of a graph is an edge-magic labeling of with the extra property that (()) = {1, 2, 3, . . . , }.A super edge-magic graph is a graph that admits a super edge-magic labeling. ese concepts were introduced by Enomoto et al. [2] in 1998. In [1], Kotzig and Rosa introduced the concept of edge- magic deficiency of a graph. ey define the edge-magic deficiency of a graph , (), as the smallest nonnegative integer such that 1 is an edge-magic graph. Motivated by Kotzig and Rosa’s concept of edge-magic deficiency, Figueroa-Centeno et al. [3] introduced the concept of super edge-magic deficiency of a graph. e super edge-magic deficiency of a graph , (), is defined as the smallest nonnegative integer such that 1 is a super edge-magic graph or +∞ if there exists no such . A chain graph is a graph with blocks 1 , 2 ,..., such that, for every , and +1 have a common vertex in such a way that the block-cut-vertex graph is a path. We will denote the chain graph with blocks 1 , 2 ,..., by [ 1 , 2 ,..., ]. If 1 = ⋅⋅⋅ = = , we will write [ 1 , 2 ,..., ] as [ () , +1 ,..., ]. If, for every , = for a given graph , then [ 1 , 2 ,..., ] is denoted by -path. Suppose that 1 , 2 ,..., −1 are the consecutive cut vertices of [ 1 , 2 ,..., ]. e string of [ 1 , 2 ,..., ] is ( − 2)-tuple ( 1 , 2 ,..., −2 ), where is the distance between and +1 , 1 − 2. We will write ( 1 , 2 ,..., −2 ) as ( () , +1 ,..., −2 ), if 1 =⋅⋅⋅= =. For any integer ≥2, let = × 2 . Let TL and DL be the graphs obtained from the ladder by adding a single diagonal and two diagonals in each rectangle of , respectively. us, |(TL )| = |(DL )| = 2, |(TL )| = 4 − 3, and |(DL )| = 5 − 4. TL and DL are called triangle ladder and diagonal ladder, respectively. Recently, the author studied the (super) edge-magic deficiency of DL -path, [ () 4 , DL , () 4 ], and 4 -path with some strings. Other results on the (super) edge-magic Hindawi International Journal of Mathematics and Mathematical Sciences Volume 2017, Article ID 5156974, 6 pages https://doi.org/10.1155/2017/5156974

New Results on the (Super) Edge-Magic Deficiency of Chain ...downloads.hindawi.com/journals/ijmms/2017/5156974.pdf · magic deficiency of a graph. They define theedge-magic deficiencyof

  • Upload
    others

  • View
    2

  • Download
    0

Embed Size (px)

Citation preview

Page 1: New Results on the (Super) Edge-Magic Deficiency of Chain ...downloads.hindawi.com/journals/ijmms/2017/5156974.pdf · magic deficiency of a graph. They define theedge-magic deficiencyof

Research ArticleNew Results on the (Super) Edge-Magic Deficiency ofChain Graphs

Ngurah Anak Agung Gede1 and Adiwijaya2

1Department of Civil Engineering, Universitas Merdeka Malang, Jl. Taman Agung No. 1, Malang 65146, Indonesia2School of Computing, Telkom University, Jl. Telekomunikasi No. 1, Bandung 40257, Indonesia

Correspondence should be addressed to Adiwijaya; [email protected]

Received 3 February 2017; Accepted 29 May 2017; Published 12 July 2017

Academic Editor: Dalibor Froncek

Copyright © 2017 Ngurah Anak Agung Gede and Adiwijaya. This is an open access article distributed under the CreativeCommons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided theoriginal work is properly cited.

Let 𝐺 be a graph of order V and size 𝑒. An edge-magic labeling of 𝐺 is a bijection 𝑓 : 𝑉(𝐺) ∪ 𝐸(𝐺) → {1, 2, 3, . . . , V + 𝑒} such that𝑓(𝑥)+𝑓(𝑥𝑦)+𝑓(𝑦) is a constant for every edge 𝑥𝑦 ∈ 𝐸(𝐺). An edge-magic labeling 𝑓 of𝐺with𝑓(𝑉(𝐺)) = {1, 2, 3, . . . , V} is called asuper edge-magic labeling. Furthermore, the edge-magic deficiency of a graph 𝐺, 𝜇(𝐺), is defined as the smallest nonnegative integer𝑛 such that 𝐺∪ 𝑛𝐾1 has an edge-magic labeling. Similarly, the super edge-magic deficiency of a graph 𝐺, 𝜇𝑠(𝐺), is either the smallestnonnegative integer 𝑛 such that 𝐺 ∪ 𝑛𝐾1 has a super edge-magic labeling or +∞ if there exists no such integer 𝑛. In this paper, weinvestigate the (super) edge-magic deficiency of chain graphs. Referring to these, we propose some open problems.

1. Introduction

Let 𝐺 be a finite and simple graph, where 𝑉(𝐺) and 𝐸(𝐺)are its vertex set and edge set, respectively. Let V = |𝑉(𝐺)|and 𝑒 = |𝐸(𝐺)| be the number of the vertices and edges,respectively. In [1], Kotzig and Rosa introduced the conceptsof edge-magic labeling and edge-magic graph as follows: anedge-magic labeling of a graph 𝐺 is a bijection 𝑓 : 𝑉(𝐺) ∪𝐸(𝐺) → {1, 2, 3, . . . , V + 𝑒} such that 𝑓(𝑥) + 𝑓(𝑥𝑦) + 𝑓(𝑦) isa constant, called the magic constant of 𝑓, for every edge 𝑥𝑦of 𝐺. A graph that admits an edge-magic labeling is called anedge-magic graph. A super edge-magic labeling of a graph 𝐺is an edge-magic labeling 𝑓 of 𝐺 with the extra property that𝑓(𝑉(𝐺)) = {1, 2, 3, . . . , 𝑒}. A super edge-magic graph is a graphthat admits a super edge-magic labeling.These concepts wereintroduced by Enomoto et al. [2] in 1998.

In [1], Kotzig and Rosa introduced the concept of edge-magic deficiency of a graph. They define the edge-magicdeficiency of a graph 𝐺, 𝜇(𝐺), as the smallest nonnegativeinteger 𝑛 such that𝐺∪𝑛𝐾1 is an edge-magic graph.Motivatedby Kotzig and Rosa’s concept of edge-magic deficiency,Figueroa-Centeno et al. [3] introduced the concept of superedge-magic deficiency of a graph. The super edge-magicdeficiency of a graph 𝐺, 𝜇𝑠(𝐺), is defined as the smallest

nonnegative integer 𝑛 such that𝐺∪𝑛𝐾1 is a super edge-magicgraph or +∞ if there exists no such 𝑛.

A chain graph is a graph with blocks 𝐵1, 𝐵2, . . . , 𝐵𝑘 suchthat, for every 𝑖, 𝐵𝑖 and 𝐵𝑖+1 have a common vertex insuch a way that the block-cut-vertex graph is a path. Wewill denote the chain graph with 𝑘 blocks 𝐵1, 𝐵2, . . . , 𝐵𝑘 by𝐶[𝐵1, 𝐵2, . . . , 𝐵𝑘]. If 𝐵1 = ⋅ ⋅ ⋅ = 𝐵𝑡 = 𝐵, we will write𝐶[𝐵1, 𝐵2, . . . , 𝐵𝑘] as𝐶[𝐵(𝑡), 𝐵𝑡+1, . . . , 𝐵𝑘]. If, for every 𝑖,𝐵𝑖 = 𝐻for a given graph 𝐻, then 𝐶[𝐵1, 𝐵2, . . . , 𝐵𝑘] is denoted by𝑘𝐻-path. Suppose that 𝑐1, 𝑐2, . . . , 𝑐𝑘−1 are the consecutive cutvertices of 𝐶[𝐵1, 𝐵2, . . . , 𝐵𝑘]. The string of 𝐶[𝐵1, 𝐵2, . . . , 𝐵𝑘]is (𝑘 − 2)-tuple (𝑑1, 𝑑2, . . . , 𝑑𝑘−2), where 𝑑𝑖 is the distancebetween 𝑐𝑖 and 𝑐𝑖+1, 1 ≤ 𝑖 ≤ 𝑘 − 2. We will write(𝑑1, 𝑑2, . . . , 𝑑𝑘−2) as (𝑑(𝑡), 𝑑𝑡+1, . . . , 𝑑𝑘−2), if 𝑑1 = ⋅ ⋅ ⋅ = 𝑑𝑡 = 𝑑.

For any integer 𝑚 ≥ 2, let 𝐿𝑚 = 𝑃𝑚 × 𝑃2. Let TL𝑚 andDL𝑚 be the graphs obtained from the ladder 𝐿𝑚 by addinga single diagonal and two diagonals in each rectangle of 𝐿𝑚,respectively. Thus, |𝑉(TL𝑚)| = |𝑉(DL𝑚)| = 2𝑚, |𝐸(TL𝑚)| =4𝑚 − 3, and |𝐸(DL𝑚)| = 5𝑚 − 4. TL𝑚 and DL𝑚 are calledtriangle ladder and diagonal ladder, respectively.

Recently, the author studied the (super) edge-magicdeficiency of 𝑘DL𝑚-path, 𝐶[𝐾(𝑘)4 ,DL𝑚, 𝐾(𝑛)4 ], and 𝑘𝐶4-pathwith some strings. Other results on the (super) edge-magic

HindawiInternational Journal of Mathematics and Mathematical SciencesVolume 2017, Article ID 5156974, 6 pageshttps://doi.org/10.1155/2017/5156974

Page 2: New Results on the (Super) Edge-Magic Deficiency of Chain ...downloads.hindawi.com/journals/ijmms/2017/5156974.pdf · magic deficiency of a graph. They define theedge-magic deficiencyof

2 International Journal of Mathematics and Mathematical Sciences

deficiency of chain graphs can be seen in [4]. The latestdevelopments in this area can be found in the survey of graphlabelings by Gallian [5]. In this paper, we further investigatethe (super) edge-magic deficiency of chain graphs whoseblocks are combination of TL𝑚 and DL𝑚 and 𝐾4 and TL𝑚,as well as the combination of 𝐶4 and 𝐿𝑚. Additionally, wepropose some open problems related to the (super) edge-magic deficiency of these graphs. To present our results, weuse the following lemmas.

Lemma 1 (see [6]). A graph 𝐺 is a super edge-magic graphif and only if there exists a bijective function 𝑓 : 𝑉(𝐺) →{1, 2, . . . , V} such that the set 𝑆 = {𝑓(𝑥) + 𝑓(𝑦) : 𝑥𝑦 ∈ 𝐸(𝐺)}consists of 𝑒 consecutive integers.Lemma 2 (see [2]). If 𝐺 is a super edge-magic graph, then 𝑒 ≤2V − 3.

2. Main Results

For 𝑘 ≥ 3, let 𝐺 = 𝐶[𝐵1, 𝐵2, . . . , 𝐵𝑘], where 𝐵𝑗 = TL𝑚 when 𝑗is odd and 𝐵𝑗 = DL𝑚 when 𝑗 is even. Thus 𝐺 is a chain graphwith |𝑉(𝐺)| = (2𝑚−1)𝑘+1 and |𝐸(𝐺)| = (1/2)(𝑘+1)(4𝑚−3)+(1/2)(𝑘−1)(5𝑚−4)when 𝑘 is odd, or |𝐸(𝐺)| = (𝑘/2)(4𝑚−3)+(𝑘/2)(5𝑚− 4) when 𝑘 is even. By Lemma 2, it can be checkedthat 𝐺 is not super edge-magic when 𝑚 ≥ 3 and 𝑘 is evenand when𝑚 ≥ 4 and 𝑘 is odd. As we can see later, when𝑚 =3 and 𝑘 is odd, 𝐺 is super edge-magic. Next, we investigatethe super edge-magic deficiency of𝐺. Our first result gives itslower bound.This result is a direct consequence of Lemma 2,so we state the result without proof.

Lemma 3. Let 𝑘 ≥ 3 be an integer. For any integer𝑚 ≥ 3,

𝜇𝑠 (𝐺)

≥{{{{{{{{{

⌊14𝑘 (𝑚 − 3)⌋ + 1, if 𝑘 is even,

⌊14 (𝑘 (𝑚 − 3) − (𝑚 − 1))⌋ + 1, if 𝑘 is odd.

(1)

Notice that the lower bound presented in Lemma 3 issharp. We found that when𝑚 is odd, the chain graph 𝐺 withparticular string has the super edge-magic deficiency equalto its lower bound as we state in Theorem 4. First, we definevertex and edge sets of 𝐵𝑗 as follows.𝑉(𝐵𝑗) = {𝑢𝑖𝑗, V𝑖𝑗 : 1 ≤ 𝑖 ≤ 𝑚}, for 1 ≤ 𝑗 ≤ 𝑘. 𝐸(𝐵𝑗) =

{𝑢𝑖𝑗𝑢𝑖+1𝑗 , V𝑖𝑗V𝑖+1𝑗 : 1 ≤ 𝑖 ≤ 𝑚 − 1} ∪ {𝑒𝑖𝑗: where 𝑒𝑖𝑗 is either𝑢𝑖𝑗V𝑖+1𝑗 or V𝑖𝑗𝑢𝑖+1𝑗 , 1 ≤ 𝑖 ≤ 𝑚−1}∪{𝑢𝑖𝑗V𝑖𝑗: 1 ≤ 𝑖 ≤ 𝑚}, for 1 ≤ 𝑗 ≤𝑘, when 𝑗 is odd, and 𝐸(𝐵𝑗) = {𝑢𝑖𝑗𝑢𝑖+1𝑗 , V𝑖𝑗V𝑖+1𝑗 , 𝑢𝑖𝑗V𝑖+1𝑗 , V𝑖𝑗𝑢𝑖+1𝑗 :1 ≤ 𝑖 ≤ 𝑚 − 1} ∪ {𝑢𝑖𝑗V𝑖𝑗 : 1 ≤ 𝑖 ≤ 𝑚}, for 1 ≤ 𝑗 ≤ 𝑘, when 𝑗 iseven.

Theorem4. Let 𝑘 ≥ 3 be an integer and𝐺 = 𝐶[𝐵1, 𝐵2, . . . , 𝐵𝑘]with string (𝑚 − 1, 𝑑1, 𝑚 − 1, 𝑑2, 𝑚 − 1, . . . , 𝑑(1/2)(𝑘−3), 𝑚 − 1)when 𝑘 is odd or (𝑚 − 1, 𝑑1, 𝑚 − 1, 𝑑2, . . . , 𝑚 − 1, 𝑑(1/2)(𝑘−2))

when 𝑘 is even, where 𝑑1, 𝑑2, . . . , 𝑑⌊(1/2)(𝑘−2)⌋ ∈ {𝑚− 1,𝑚}. Forany odd integer𝑚 ≥ 3,

𝜇𝑠 (𝐺) ={{{{{{{

14𝑘 (𝑚 − 3) + 1, if 𝑘 is even,14 (𝑘 − 1) (𝑚 − 3) , if 𝑘 is odd.

(2)

Proof. First, we define 𝐺 as a graph with vertex set 𝑉(𝐺) =⋃𝑘𝑗=1 𝑉(𝐵𝑗), where 𝑢𝑚𝑗 = V1𝑗+1, 1 ≤ 𝑗 ≤ 𝑘 − 1, and edge set𝐸(𝐺) = ⋃𝑘𝑗=1 𝐸(𝐵𝑗). Under this definition, 𝑢𝑚𝑗 = V1𝑗+1, 1 ≤ 𝑗 ≤𝑘 − 1, are the cut vertices of 𝐺.

Next, for 1 ≤ 𝑖 ≤ 𝑚 and 1 ≤ 𝑗 ≤ 𝑘, define the labeling𝑓 : 𝑉(𝐺) ∪ 𝛼𝐾1 → {1, 2, 3, . . . , (2𝑚 − 1)𝑘 + 1 + 𝛼}, where𝛼 = (1/4)𝑘(𝑚−3)+1when 𝑘 is even or 𝛼 = (1/4)(𝑘−1)(𝑚−3)when 𝑘 is odd, as follows:𝑓 (𝑥)

=

{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{

14 (𝑗 − 1) (9𝑚 − 7) + 2𝑖 − 1, if 𝑥 = 𝑢𝑖𝑗, 𝑗 is odd,14 (𝑗 − 1) (9𝑚 − 7) + 2𝑖, if 𝑥 = V𝑖𝑗, 𝑗 is odd,

𝛽 + 12 (5𝑖 − 3) , if 𝑥 = 𝑢𝑖𝑗, 𝑖 is odd, 𝑗 is even,

𝛽 + 12 (5𝑖 − 4) , if 𝑥 = 𝑢𝑖𝑗, 𝑖 is even, 𝑗 is even,

𝛽 + 12 (5𝑖 − 7) , if 𝑥 = V𝑖𝑗, 𝑖 is odd, 𝑗 is even,

𝛽 + 12 (5𝑖 − 6) , if 𝑥 = V𝑖𝑗, 𝑖 is even, 𝑗 is even,

(3)

where 𝛽 = (1/4)(𝑗 − 2)(9𝑚 − 7) + 2𝑚.Under the vertex labeling 𝑓, it can be checked that no

labels are repeated, 𝑓(𝑢𝑚𝑗 ) = 𝑓(V1𝑗+1), 1 ≤ 𝑗 ≤ 𝑘 − 1,{𝑓(𝑥) + 𝑓(𝑦) : 𝑥𝑦 ∈ 𝐸(𝐺)} is a set of |𝐸(𝐺)| consecutiveintegers, and the largest vertex label used is (1/4)(𝑘−2)(9𝑚−7)+(1/2)(9𝑚−3)when 𝑘 is even or (1/4)(𝑘−1)(9𝑚−7)+2𝑚when 𝑘 is odd. Also, it can be checked that 𝑓(𝑢𝑖𝑗) + 𝑓(V𝑖+1𝑗 ) =𝑓(V𝑖𝑗) + 𝑓(𝑢𝑖+1𝑗 ) when 𝑗 is odd.

Next, label the isolated vertices in the following way.

Case 𝑘 Is Odd. In this case, we denote the isolated verticeswith{ 𝑧𝑙2𝑗−1 | 1 ≤ 𝑙 ≤ (1/2)(𝑚 − 3), 1 ≤ 𝑗 ≤ (1/2)(𝑘 − 1)} and set𝑓(𝑧𝑙2𝑗−1) = 𝑓(V𝑚2𝑗−1) + 5𝑙.Case 𝑘 Is Even. In this case, we denote the isolated verticeswith {𝑧𝑙2𝑗−1 | 1 ≤ 𝑙 ≤ (1/2)(𝑚 − 3), 1 ≤ 𝑗 ≤ 𝑘/2} ∪ {𝑧0} and set𝑓(𝑧𝑙2𝑗−1) = 𝑓(V𝑚2𝑗−1) + 5𝑙 and 𝑓(𝑧0) = 𝑓(V𝑚𝑘 ) + 1.

By Lemma 1, 𝑓 can be extended to a super edge-magiclabeling of𝐺∪𝛼𝐾1 with themagic constant (𝑘/4)(27𝑚−21)+5when 𝑘 is even or (1/4)(𝑘 − 1)(27𝑚 − 21) + 6𝑚 when 𝑘 isodd. Based on these facts and Lemma 3, we have the desiredresult.

An example of the labeling defined in the proof ofTheorem 4 is shown in Figure 1(a).

Notice that when 𝑚 = 3 and 𝑘 is odd, 𝜇𝑠(𝐺) = 0.In other words, the chain graph 𝐺 with string (2, 𝑑1, 2, 𝑑2,2, . . . , 𝑑(1/2)(𝑘−3), 2), where 𝑑𝑖 ∈ {2, 3}, is super edge-magic

Page 3: New Results on the (Super) Edge-Magic Deficiency of Chain ...downloads.hindawi.com/journals/ijmms/2017/5156974.pdf · magic deficiency of a graph. They define theedge-magic deficiencyof

International Journal of Mathematics and Mathematical Sciences 3

2 6 10

912 14 17 19

2123 25 27 29

39 41 43 45 47

42 44 46 4840

28

31 33 36 38

1 5

11 13 16 18

20 22 24 26

30 32 35 37

15

34

84

3 7

(a)

52

33

676665

2019

21 43

4140

65

4342 108

97

4544

1211

26251618 1517

6264

3739

4749

2830 2729

4648

5658

2221

6163

36385154

3134

3235 5053

1314

5960

5557

2423

(b)

Figure 1: (a) Vertex labeling of 𝐶[TL5,DL5,TL5,DL5,TL5] ∪ 2𝐾1 with string (4, 5, 4). (b) Vertex and edge labelings of 𝑐[𝐶(3+2)4 , 𝐿4, 𝐶(2)4 ] withstring (2, 1(2), 2, 4, 2).

when 𝑚 = 3 and 𝑘 is odd. Based on this fact and previousresults, we propose the following open problems.

Open Problem 1. Let 𝑘 ≥ 3 be an integer. For𝑚 = 2, decide ifthere exists a super edge-magic labeling of𝐺. Further, for anyeven integer 𝑚 ≥ 2, find the super edge-magic deficiency of𝐺.

Next, we investigate the super edge-magic deficiencyof the chain graph 𝐻 = 𝐶[𝐾(𝑝)4 ,TL𝑚, 𝐾(𝑞)4 ] with string(1(𝑝−1), 𝑑, 1(𝑞−1)), where 𝑑 ∈ {𝑚 − 1,𝑚}.𝐻 is a graph of order3(𝑝 + 𝑞) + 2𝑚 and size 6(𝑝 + 𝑞) + 4𝑚 − 3. We define thevertex and edge sets of 𝐻 as follows: 𝑉(𝐻) = {𝑎𝑖, 𝑏𝑖: 1 ≤ 𝑖 ≤𝑝} ∪ {𝑐𝑖: 1 ≤ 𝑖 ≤ 𝑝 + 1} ∪ {𝑢𝑗, V𝑗: 1 ≤ 𝑗 ≤ 𝑚} ∪ {𝑥𝑡, 𝑦𝑡: 1 ≤𝑡 ≤ 𝑞} ∪ {𝑧𝑡: 1 ≤ 𝑡 ≤ 𝑞 + 1}, where 𝑐𝑝+1 = 𝑢1 andV𝑚 = 𝑧1, and 𝐸(𝐻) = {𝑎𝑖𝑏𝑖, 𝑎𝑖𝑐𝑖, 𝑎𝑖𝑐𝑖+1, 𝑏𝑖𝑐𝑖, 𝑏𝑖𝑐𝑖+1, 𝑐𝑖𝑐𝑖+1: 1 ≤𝑖 ≤ 𝑝} ∪ {𝑢𝑗V𝑗 | 1 ≤ 𝑗 ≤ 𝑚} ∪ {𝑢𝑗𝑢𝑗+1, V𝑗V𝑗+1: 1 ≤ 𝑗 ≤𝑚 − 1} ∪ {𝑒𝑗: 𝑒𝑗 is either 𝑢𝑗V𝑗+1 or V𝑗𝑢𝑗+1, 1 ≤ 𝑗 ≤ 𝑚 − 1} ∪{𝑥𝑡𝑦𝑡, 𝑥𝑡𝑧𝑡, 𝑥𝑡𝑧𝑡+1, 𝑦𝑡𝑧𝑡, 𝑦𝑡𝑧𝑡+1, 𝑧𝑡𝑧𝑡+1: 1 ≤ 𝑡 ≤ 𝑞}. Hence, thecut vertices of 𝐻 are 𝑐𝑖, 2 ≤ 𝑖 ≤ 𝑝 + 1, and 𝑧𝑡, 1 ≤ 𝑡 ≤ 𝑞.Notice that 𝐻 has string (1(𝑝−1), 𝑚 − 1, 1(𝑞−1)), if at least oneof 𝑒𝑗 is 𝑢𝑗V𝑗+1, and its string is (1(𝑝−1), 𝑚, 1(𝑞−1)), if 𝑒𝑗 = V𝑗𝑢𝑗+𝑖for every 1 ≤ 𝑗 ≤ 𝑚 − 1.Theorem 5. For any integers 𝑝, 𝑞 ≥ 1 and𝑚 ≥ 2, 𝜇𝑠(𝐻) = 0.

Proof. Define a bijective function 𝑔 : 𝑉(𝐻) →{1, 2, 3, . . . , 3(𝑝 + 𝑞) + 2𝑚} as follows:𝑔 (𝑥)

=

{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{

3𝑖 − 2, if 𝑥 = 𝑎𝑖, 1 ≤ 𝑖 ≤ 𝑝,3𝑖, if 𝑥 = 𝑏𝑖, 1 ≤ 𝑖 ≤ 𝑝,3𝑖 − 1, if 𝑥 = 𝑐𝑖, 1 ≤ 𝑖 ≤ 𝑝 + 1,3𝑝 + 2𝑗, if 𝑥 = 𝑢𝑗, 1 ≤ 𝑗 ≤ 𝑚,3𝑝 + 2𝑗 − 1, if 𝑥 = V𝑗, 1 ≤ 𝑗 ≤ 𝑚,3𝑝 + 2𝑚 + 3𝑡 − 2, if 𝑥 = 𝑥𝑡, 1 ≤ 𝑡 ≤ 𝑞,3𝑝 + 2𝑚 + 3𝑡, if 𝑥 = 𝑦𝑡, 1 ≤ 𝑡 ≤ 𝑞,3𝑝 + 2𝑚 + 3𝑡 − 4, if 𝑥 = 𝑧𝑡, 1 ≤ 𝑡 ≤ 𝑞 + 1.

(4)

Under the labeling 𝑔, it can be checked that 𝑔(𝑐𝑝+1) =𝑔(𝑢1) and 𝑔(V𝑚) = 𝑔(𝑧1). Also, it can be checked that 𝑔(𝑢𝑗) +𝑔(V𝑗+1) = 𝑔(V𝑗) + 𝑔(𝑢𝑗+1), 1 ≤ 𝑗 ≤ 𝑚 − 1, and {𝑔(𝑥) + 𝑔(𝑦) |𝑥𝑦 ∈ 𝐸(𝐻)} = {3, 4, 5, . . . , 6(𝑝 + 𝑞) + 4𝑚 − 1}. By Lemma 1, 𝑔can be extended to a super edge-magic labeling of𝐻with themagic constant 9(𝑝 + 𝑞) + 6𝑚. Hence, 𝜇𝑠(𝐻) = 0.Open Problem 2. For any integers𝑝, 𝑞 ≥ 1 and𝑚 ≥ 2, find thesuper edge-magic deficiency of𝐶[𝐾(𝑝)4 ,TL𝑚, 𝐾(𝑞)4 ]with string(1(𝑝−1), 𝑑, 1(𝑞−1)), where 𝑑 ∈ {1, 2, 3, . . . , 𝑚 − 2}.

Page 4: New Results on the (Super) Edge-Magic Deficiency of Chain ...downloads.hindawi.com/journals/ijmms/2017/5156974.pdf · magic deficiency of a graph. They define theedge-magic deficiencyof

4 International Journal of Mathematics and Mathematical Sciences

Next, we study the edge-magic deficiency of ladder 𝐿𝑚and chain graphs whose blocks are combination of 𝐶4 and𝐿𝑚 with some strings. In [6], Figueroa-Centeno et al. provedthat the ladder 𝐿𝑚 is super edge-magic for any odd 𝑚 andsuspected that 𝐿𝑚 is super edge-magic for any even 𝑚 > 2.Here, we can prove that 𝐿𝑚 is edge-magic for any 𝑚 ≥ 2by showing its edge-magic deficiency is zero. The result ispresented inTheorem 6.

Theorem 6. For any integer𝑚 ≥ 2, 𝜇(𝐿𝑚) = 0.Proof. Let 𝑉(𝐿𝑚) = {𝑢𝑖, V𝑖 : 1 ≤ 𝑖 ≤ 𝑚} and 𝐸(𝐺) ={𝑢𝑖𝑢𝑖+1, V𝑖V𝑖+1: 1 ≤ 𝑖 ≤ 𝑚 − 1} ∪ {𝑢𝑖V𝑖 : 1 ≤ 𝑖 ≤ 𝑚} be thevertex set and edge set, respectively, of 𝐿𝑚. It is easy to verifythat the labeling ℎ : 𝑉(𝐿𝑚)∪𝐸(𝐿𝑚) → {1, 2, 3, . . . , 5𝑚−2} is abijection and, for every𝑥𝑦 ∈ 𝐸(𝐿𝑚), ℎ(𝑥)+ℎ(𝑥𝑦)+ℎ(𝑦) = 6𝑚.

ℎ (𝑥) =

{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{

𝑖, if 𝑥 = 𝑢𝑖, 𝑖 is odd,3𝑚 + 12 (𝑖 − 2) , if 𝑥 = 𝑢𝑖, 𝑖 is even,

𝑚 + 12 (𝑖 + 1) , if 𝑥 = V𝑖, 𝑖 is odd,𝑖, if 𝑥 = V𝑖, 𝑖 is even,3𝑚 − 12 (3𝑖 − 1) , if 𝑥 = 𝑢𝑖𝑢𝑖+1, 𝑖 is odd,

3𝑚 − 32 𝑖, if 𝑥 = 𝑢𝑖𝑢𝑖+1, 𝑖 is even,

5𝑚 − 32 (𝑖 + 1) , if 𝑥 = V𝑖V𝑖+1, 𝑖 is odd,

5𝑚 − 12 (3𝑖 + 2) , if 𝑥 = V𝑖V𝑖+1, 𝑖 is even,

5𝑚 − 12 (3𝑖 + 1) , if 𝑥 = 𝑢𝑖V𝑖, 𝑖 is odd,

3𝑚 − 12 (3𝑖 − 2) , if 𝑥 = 𝑢𝑖V𝑖, 𝑖 is even.

(5)

Thus, 𝜇(𝐿𝑚) = 0 for every𝑚 ≥ 2.Theorem 7. Let 𝑝 and 𝑞 ≥ 1 be integers.

(a) If 𝑚 ≥ 2 is an even integer and 𝐹1 = 𝐶[𝐶(𝑝)4 , 𝐿𝑚, 𝑐(𝑞)4 ]with string (2(𝑝−1), 𝑚, 2(𝑞−1)), then 𝜇(𝐹1) = 0.

(b) If 𝑚 ≥ 3 is an odd integer and 𝐹2 = 𝐶[𝐶(𝑝)4 , 𝐿𝑚, 𝑐(𝑞)4 ]with string (2(𝑝−1), 𝑚 − 1, 2(𝑞−1)), then 𝜇(𝐹2) = 0.

Proof. (a) First, we introduce a constant 𝜆 as follows: 𝜆 = 1, if𝑚 is odd and 𝜆 = 2, if𝑚 is even. Next, we define 𝐹1 as a graphwith𝑉(𝐹1) = {𝑎𝑖, 𝑏𝑖: 1 ≤ 𝑖 ≤ 𝑝}∪{𝑐𝑖: 1 ≤ 𝑖 ≤ 𝑝+1}∪{𝑢𝑗, V𝑗: 1 ≤𝑗 ≤ 𝑚} ∪ {𝑥𝑡, 𝑦𝑡: 1 ≤ 𝑡 ≤ 𝑞} ∪ {𝑧𝑡: 1 ≤ 𝑡 ≤ 𝑞 + 1}, where𝑐𝑝+1 = V1 and 𝑢𝑚 = 𝑧1, and 𝐸(𝐻) = {𝑐𝑖𝑎𝑖, 𝑐𝑖𝑏𝑖, 𝑎𝑖𝑐𝑖+1, 𝑏𝑖𝑐𝑖+1: 1 ≤𝑖 ≤ 𝑝} ∪ {𝑢𝑗V𝑗 | 1 ≤ 𝑗 ≤ 𝑚} ∪ {𝑢𝑗𝑢𝑗+1, V𝑗V𝑗+1: 1 ≤ 𝑗 ≤𝑚− 1} ∪ {𝑧𝑡𝑥𝑡, 𝑧𝑡𝑦𝑡, 𝑥𝑡𝑧𝑡+1, 𝑦𝑡𝑧𝑡+1: 1 ≤ 𝑡 ≤ 𝑞}.The cut verticesof 𝐹1 are 𝑐𝑖, 2 ≤ 𝑖 ≤ 𝑝 + 1, and 𝑧𝑡, 1 ≤ 𝑡 ≤ 𝑞.

Next, define a bijection 𝑓1 : 𝑉(𝐹1) ∪ 𝐸(𝐹1) → {1, 2, 3, . . . ,7(𝑝 + 𝑞) + 5𝑚 − 2} as follows:

𝑓1 (𝑥)

=

{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{

4 (𝑝 + 𝑞) + 3𝑚 + 𝑖 − 1, if 𝑥 = 𝑎𝑖, 1 ≤ 𝑖 ≤ 𝑝,𝑝 + 𝑞 + 𝑚 + 𝑖, if 𝑥 = 𝑏𝑖, 1 ≤ 𝑖 ≤ 𝑝,𝑖, if 𝑥 = 𝑐𝑖, 1 ≤ 𝑖 ≤ 𝑝 + 1,5𝑝 + 4𝑞 + 3𝑚 + 12 (𝑗 − 1) , if 𝑥 = 𝑢𝑗, 𝑗 is odd,𝑝 + 𝑗, if 𝑥 = 𝑢𝑗, 𝑗 is even,𝑝 + 𝑗, if 𝑥 = V𝑗, 𝑗 is odd,2𝑝 + 𝑞 + 𝑚 + 𝑗2 , if 𝑥 = V𝑗, 𝑗 is even,5𝑝 + 4𝑞 + 𝛾1 + 𝑡, if 𝑥 = 𝑥𝑡, 1 ≤ 𝑡 ≤ 𝑞,2𝑝 + 𝑞 + 𝛾2 + 𝑡, if 𝑥 = 𝑦𝑡, 1 ≤ 𝑡 ≤ 𝑞,𝑝 + 𝑚 + 𝑡 − 1, if 𝑥 = 𝑧𝑡, 1 ≤ 𝑡 ≤ 𝑞 + 1,4 (𝑝 + 𝑞) + 3𝑚 + 1 − 2𝑖, if 𝑥 = 𝑐𝑖𝑎𝑖, 1 ≤ 𝑖 ≤ 𝑝,7 (𝑝 + 𝑞) + 5𝑚 − 2𝑖, if 𝑥 = 𝑐𝑖𝑏𝑖, 1 ≤ 𝑖 ≤ 𝑝,4 (𝑝 + 𝑞) + 3𝑚 − 2𝑖, if 𝑥 = 𝑎𝑖𝑐𝑖+1, 1 ≤ 𝑖 ≤ 𝑝,7 (𝑝 + 𝑞) + 5𝑚 − 1 − 2𝑖, if 𝑥 = 𝑏𝑖𝑐𝑖+1, 1 ≤ 𝑖 ≤ 𝑝,2𝑝 + 4𝑞 + 3𝑚 − 12 (3𝑗 + 1) , if 𝑥 = 𝑢𝑗𝑢𝑗+1, 𝑗 is odd,2𝑝 + 4𝑞 + 3𝑚 − 12 (3𝑗) , if 𝑥 = 𝑢𝑗𝑢𝑗+1, 𝑗 is even,5𝑝 + 7𝑞 + 5𝑚 − 12 (3𝑗 + 1) , if 𝑥 = V𝑗V𝑗+1, 𝑗 is odd,5𝑝 + 7𝑞 + 5𝑚 − 12 (3𝑗 + 2) , if 𝑥 = V𝑗V𝑗+1, 𝑗 is even,2𝑝 + 4𝑞 + 3𝑚 − 12 (3𝑖 − 1) , if 𝑥 = 𝑢𝑗V𝑗, 𝑗 is odd,5𝑝 + 7𝑞 + 5𝑚 − 32𝑗, if 𝑥 = 𝑢𝑗V𝑗, 𝑗 is even,2𝑝 + 4𝑞 + 𝛾3 − 2𝑡 if 𝑥 = 𝑧𝑡𝑥𝑡, 1 ≤ 𝑡 ≤ 𝑞,5𝑝 + 7𝑞 + 𝛾4 − 2𝑡, if 𝑥 = 𝑧𝑡𝑦𝑡, 1 ≤ 𝑡 ≤ 𝑞,2𝑝 + 4𝑞 + 𝛾5 − 2𝑡, if 𝑥 = 𝑥𝑡𝑧𝑡+1, 1 ≤ 𝑡 ≤ 𝑞,5𝑝 + 7𝑞 + 𝛾6 − 2𝑡, if 𝑥 = 𝑦𝑡𝑧𝑡+1, 1 ≤ 𝑡 ≤ 𝑞,

(6)

where 𝛾1 = (1/2)(𝜆 − 1)(7𝑚 − 2) − (1/2)(𝜆 − 2)(7𝑚 − 1), 𝛾2 =(1/2)(𝜆−1)(3𝑚)−(1/2)(𝜆−2)(3𝑚−1), 𝛾3 = (1/2)(𝜆−1)(3𝑚+4)−(1/2)(𝜆−2)(3𝑚+3), 𝛾4 = (1/2)(𝜆−1)(7𝑚+2)−(1/2)(𝜆−2)(7𝑚 + 3), 𝛾5 = (1/2)(𝜆 − 1)(3𝑚 + 2) − (1/2)(𝜆 − 2)(3𝑚 + 1),and 𝛾6 = (1/2)(𝜆 − 1)(7𝑚) − (1/2)(𝜆 − 2)(7𝑚+ 1). It is easy toverify that, for every edge 𝑥𝑦 ∈ 𝐸(𝐹1), 𝑓(𝑥) + 𝑓(𝑥𝑦) + 𝑓(𝑦) =8(𝑝 + 𝑞) + 6𝑚.

(b) We define 𝐹2 as graph with 𝑉(𝐹2) = 𝑉(𝐹1), where𝑐𝑝+1 = V1 and V𝑚 = 𝑧1, and 𝐸(𝐹2) = 𝐸(𝐹1). Under thisdefinition, the cut vertices of 𝐹2 are 𝑐𝑖, 2 ≤ 𝑖 ≤ 𝑝 + 1, and𝑧𝑡, 1 ≤ 𝑡 ≤ 𝑞.Next, we define a bijection𝑓2 : 𝑉(𝐹2)∪𝐸(𝐹2) →{1, 2, 3, . . . , 7(𝑝 + 𝑞) + 5𝑚 − 2}, where 𝑓2(𝑥) = 𝑓1(𝑥) for all𝑥 ∈ 𝑉(𝐹2) ∪ 𝐸(𝐹2). It can be checked that 𝑓2 is an edge-magiclabeling of 𝐹2 with the magic constant 8(𝑝 + 𝑞) + 6𝑚.Open Problem 3. Let 𝑝 and 𝑞 ≥ 1 be integers.

(a) If 𝑚 ≥ 3 is an odd integer, find the super edge-magicdeficiency of 𝐶[𝐶(𝑝)4 , 𝐿𝑚, 𝑐(𝑞)4 ] with string (2(𝑝−1),𝑚, 2(𝑞−1)).

(b) If𝑚 ≥ 2 is an even integer, find the super edge-magicdeficiency of 𝐶[𝐶(𝑝)4 , 𝐿𝑚, 𝑐(𝑞)4 ] with string (2(𝑝−1), 𝑚 −1, 2(𝑞−1)).

Page 5: New Results on the (Super) Edge-Magic Deficiency of Chain ...downloads.hindawi.com/journals/ijmms/2017/5156974.pdf · magic deficiency of a graph. They define theedge-magic deficiencyof

International Journal of Mathematics and Mathematical Sciences 5

Theorem 8. Let 𝑝, 𝑞 ≥ 2 and 𝑟 ≥ 1 be integers.(a) If𝑚 ≥ 2 is an even integer and𝐻1 = 𝐶[𝐶(𝑝+𝑞)4 , 𝐿𝑚, 𝑐(𝑟)4 ]

with string (2(𝑝−2), 1(2), 2(𝑞−1), 𝑚, 2(𝑟−1)), then 𝜇(𝐻1) = 0.(b) If𝑚 ≥ 3 is an odd integer and𝐻2 = 𝐶[𝐶(𝑝+𝑞)4 , 𝐿𝑚, 𝑐(𝑟)4 ]

with string (2(𝑝−2), 1(2),2(𝑞−1),𝑚−1,2(𝑟−1)), then 𝜇(𝐻2) = 0.Proof. (a) First, we define𝐻1 as a graphwith𝑉(𝐻1) = {𝑎𝑖: 1 ≤𝑖 ≤ 2𝑝} ∪ {𝑏𝑖: 1 ≤ 𝑖 ≤ 𝑝 + 1} ∪ {𝑢𝑗: 1 ≤ 𝑗 ≤ 2𝑞} ∪

{V𝑗: 1 ≤ 𝑗 ≤ 𝑞 + 1} ∪ {𝑤𝑠: 1 ≤ 𝑠 ≤ 2𝑚} ∪ {𝑥𝑡: 1 ≤ 𝑡 ≤2𝑟} ∪ {𝑦𝑡: 1 ≤ 𝑡 ≤ 𝑟 + 1}, where 𝑎2𝑝 = 𝑢1, V𝑞+1 = 𝑤1,and 𝑤2𝑚 = 𝑦1, and 𝐸(𝐻1) = {𝑏𝑖𝑎𝑖, 𝑏𝑖𝑎𝑝+𝑖, 𝑎𝑖𝑏𝑖+1, 𝑎𝑝+𝑖𝑏𝑖+1: 1 ≤𝑖 ≤ 𝑝} ∪ {V𝑗𝑢𝑗, V𝑗𝑢𝑞+𝑗, 𝑢𝑗V𝑗+1, 𝑢𝑞+𝑗V𝑗+1 | 1 ≤ 𝑗 ≤ 𝑞} ∪{𝑤𝑠𝑤𝑠+1, 𝑤𝑚+𝑠𝑤𝑚+𝑠+1 : 1 ≤ 𝑠 ≤ 𝑚 − 1} ∪ {𝑤𝑠𝑤𝑚+𝑠: 1 ≤ 𝑠 ≤𝑚} ∪ {𝑦𝑡𝑥𝑡, 𝑦𝑡𝑥𝑟+𝑡, 𝑥𝑡𝑦𝑡+1, 𝑥𝑟+𝑡𝑦𝑡+1: 1 ≤ 𝑡 ≤ 𝑟}.

Next, define a bijection 𝑔1 : 𝑉(𝐻1) ∪ 𝐸(𝐻1) → {1, 2,3, . . . , 7(𝑝 + 𝑞 + 𝑟) + 5𝑚 − 2} as follows:

𝑔1 (𝑧) =

{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{

6𝑝 + 7 (𝑞 + 𝑟) + 5𝑚 + 𝑖 − 2, if 𝑧 = 𝑎𝑖, 1 ≤ 𝑖 ≤ 𝑝,3𝑝 + 𝑞 + 𝑟 + 𝑚 + 1 + 𝑖, if 𝑧 = 𝑎𝑝+𝑖, 1 ≤ 𝑖 ≤ 𝑝,𝑖, if 𝑧 = 𝑏𝑖, 1 ≤ 𝑖 ≤ 𝑝 + 1,4𝑝 + 𝑞 + 𝑟 + 𝑚 + 𝑗, if 𝑧 = 𝑢𝑗, 1 ≤ 𝑗 ≤ 𝑞,4 (𝑝 + 𝑞 + 𝑟) + 3𝑚 + 𝑗 − 1, if 𝑧 = 𝑢𝑞+𝑗, 1 ≤ 𝑗 ≤ 𝑞,𝑝 + 1 + 𝑗, if 𝑧 = V𝑗, 1 ≤ 𝑗 ≤ 𝑞 + 1,𝑝 + 𝑞 + 1 + 𝑠, if 𝑧 = 𝑤𝑠, 𝑠 is odd,4𝑝 + 2𝑞 + 𝑟 + 𝑚 + 12𝑠, if 𝑧 = 𝑤𝑠, 𝑠 is even,4𝑝 + 5𝑞 + 4𝑟 + 3𝑚 + 12 (𝑠 − 1) , if 𝑧 = 𝑤𝑚+𝑠, 𝑠 is odd,𝑝 + 𝑞 + 1 + 𝑠, if 𝑧 = 𝑤𝑚+𝑠, 𝑠 is even,

𝑔1 (𝑧) =

{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{

4𝑝 + 2𝑞 + 𝑟 + 𝛾2 + 𝑡, if 𝑧 = 𝑥𝑡, 1 ≤ 𝑡 ≤ 𝑟,4𝑝 + 5𝑞 + 4𝑟 + 𝛾1 + 𝑡, if 𝑧 = 𝑥𝑟+𝑡, 1 ≤ 𝑡 ≤ 𝑟,𝑝 + 𝑞 + 𝑚 + 𝑡, if 𝑧 = 𝑦𝑡, 1 ≤ 𝑡 ≤ 𝑟 + 1,3𝑝 + 𝑞 + 𝑟 + 𝑚 + 3 − 2𝑖, if 𝑧 = 𝑏𝑖𝑎𝑖, 1 ≤ 𝑖 ≤ 𝑝,6𝑝 + 7 (𝑞 + 𝑟) + 5𝑚 − 2𝑖, if 𝑧 = 𝑏𝑖𝑎𝑝+𝑖, 1 ≤ 𝑖 ≤ 𝑝,3𝑝 + 𝑞 + 𝑟 + 𝑚 + 2 − 2𝑖, if 𝑧 = 𝑎𝑖𝑏𝑖+1, 1 ≤ 𝑖 ≤ 𝑝,6𝑝 + 7 (𝑞 + 𝑟) + 5𝑚 − 2𝑖 − 1, if 𝑧 = 𝑎𝑝+𝑖𝑏𝑖+1, 1 ≤ 𝑖 ≤ 𝑝,4𝑝 + 7 (𝑞 + 𝑟) + 5𝑚 − 2𝑗, if 𝑧 = V𝑗𝑢𝑗, 1 ≤ 𝑗 ≤ 𝑞,4 (𝑝 + 𝑞 + 𝑟) + 3𝑚 + 1 − 2𝑗, if 𝑧 = V𝑗𝑢𝑞+𝑗, 1 ≤ 𝑗 ≤ 𝑞,4𝑝 + 7 (𝑞 + 𝑟) + 5𝑚 − 2𝑗 − 1, if 𝑧 = 𝑢𝑗V𝑗+1, 1 ≤ 𝑗 ≤ 𝑞,4 (𝑝 + 𝑞 + 𝑟) + 3𝑚 − 2𝑗, if 𝑧 = 𝑢𝑞+𝑗V𝑗+1, 1 ≤ 𝑗 ≤ 𝑞,4𝑝 + 5𝑞 + 7𝑟 + 5𝑚 − 12 (3𝑠 + 1) , if 𝑧 = 𝑤𝑠𝑤𝑠+1, 𝑠 is odd,4𝑝 + 5𝑞 + 7𝑟 + 5𝑚 − 12 (3𝑠 + 2) , if 𝑧 = 𝑤𝑠𝑤𝑠+1, 𝑠 is even,4𝑝 + 2𝑞 + 4𝑟 + 3𝑚 − 12 (3𝑠 + 1) , if 𝑧 = 𝑤𝑚+𝑠𝑤𝑚+𝑠+1, 𝑠 is odd,4𝑝 + 2𝑞 + 4𝑟 + 3𝑚 − 12 (3𝑠) , if 𝑧 = 𝑤𝑚+𝑠𝑤𝑚+𝑠+1, 𝑠 is even,4𝑝 + 2𝑞 + 4𝑟 + 3𝑚 − 12 (3𝑠 − 1) , if 𝑧 = 𝑤𝑠𝑤𝑚+𝑠, 𝑠 is odd,4𝑝 + 5𝑞 + 7𝑟 + 5𝑚 − 32𝑠, if 𝑧 = 𝑤𝑠𝑤𝑚+𝑠, 𝑠 is even,4𝑝 + 5𝑞 + 7𝑟 + 𝛾4 − 2𝑡, if 𝑧 = 𝑦𝑡𝑥𝑡, 1 ≤ 𝑡 ≤ 𝑟,4𝑝 + 2𝑞 + 4𝑟 + 𝛾3 − 2𝑡, if 𝑧 = 𝑦𝑡𝑥𝑟+𝑡, 1 ≤ 𝑡 ≤ 𝑟,4𝑝 + 5𝑞 + 7𝑟 + 𝛾6 − 2𝑡, if 𝑧 = 𝑥𝑡𝑦𝑡+1, 1 ≤ 𝑡 ≤ 𝑟,4𝑝 + 2𝑞 + 4𝑟 + 𝛾5 − 2𝑡, if 𝑧 = 𝑥𝑟+𝑡𝑦𝑡+1, 1 ≤ 𝑡 ≤ 𝑟,

(7)

Page 6: New Results on the (Super) Edge-Magic Deficiency of Chain ...downloads.hindawi.com/journals/ijmms/2017/5156974.pdf · magic deficiency of a graph. They define theedge-magic deficiencyof

6 International Journal of Mathematics and Mathematical Sciences

where 𝛾1, 𝛾2, 𝛾3, 𝛾4, 𝛾5, 𝛾6, and 𝜆 are defined as in the proof ofTheorem 7. It can be checked that, for every edge 𝑥𝑦 ∈ 𝐸(𝐻1),𝑔1(𝑥)+𝑔1(𝑥𝑦)+𝑔1(𝑦) = 9𝑝+8(𝑞+𝑟)+6𝑚+1.Hence𝜇(𝐻1) = 0.

An illustration of the labeling defined in the proof ofTheorem 8 is given in Figure 1(b).

(b) We define 𝐻2 as graph with 𝑉(𝐻2) = 𝑉(𝐻1), where𝑎2𝑝 = 𝑢1, V𝑞+1 = 𝑤1, and 𝑤𝑚 = 𝑦1, and 𝐸(𝐻2) = 𝐸(𝐻1). It canbe checked that𝑔2 : 𝑉(𝐻2)∪𝐸(𝐻2) → {1, 2, 3, . . . , 7(𝑝+𝑞+𝑟)+5𝑚 − 2} defined by 𝑔2(𝑥) = 𝑔1(𝑥), for all 𝑥 ∈ 𝑉(𝐻2) ∪ 𝐸(𝐻2),is an edge-magic labeling of𝐻2 with the magic constant 9𝑝+8(𝑞 + 𝑟) + 6𝑚 + 1.Open Problem 4. Let 𝑝, 𝑞 ≥ 2 and 𝑟 ≥ 1 be integers.

(a) If 𝑚 ≥ 3 is an odd integer, find the edge-magic defi-ciency of 𝐶[𝐶(𝑝)4 , 𝑐(𝑞)4 , 𝐿𝑚, 𝑐(𝑟)4 ] with string (2(𝑝−2), 1(2),2(𝑞−1), 𝑚, 2(𝑟−1)).

(b) If 𝑚 ≥ 2 is an even integer, find the edge-magic defi-ciency of 𝐶[𝐶(𝑝)4 , 𝑐(𝑞)4 , 𝐿𝑚, 𝑐(𝑟)4 ] with string (2(𝑝−2), 1(2),2(𝑞−1), 𝑚 − 1, 2(𝑟−1)).

Conflicts of Interest

The authors declare that there are no conflicts of interestregarding the publication of this paper.

Acknowledgments

The first author has been supported by “Hibah Kompetensi2016” (018/SP2H/P/K7/KM/2016) from the Directorate Gen-eral of Higher Education, Indonesia.

References

[1] A. Kotzig and A. Rosa, “Magic valuations of finite graphs,”Canadian Mathematical Bulletin, vol. 13, pp. 451–461, 1970.

[2] H. Enomoto, A. S. Llado, T. Nakamigawa, and G. Ringel, “Superedge-magic graphs,” SUT Journal of Mathematics, vol. 34, no. 2,pp. 105–109, 1998.

[3] R. M. Figueroa-Centeno, R. Ichishima, and F. A. Muntaner-Batle, “On the super edge-magic deficiency of graphs,” Elec-tronic Notes in Discrete Mathematics, vol. 11, pp. 299–314, 2002.

[4] A. A. Ngurah, E. T. Baskoro, and R. Simanjuntak, “On superedge-magic deficiency of graphs,” Australasian Journal of Com-binatorics, vol. 40, pp. 3–14, 2008.

[5] J. A. Gallian, “A dinamic survey of graph labelings,” Electron. J.Combin, vol. 16, 2015, DS6.

[6] R. M. Figueroa-Centeno, R. Ichishima, and F. A. Muntaner-Batle, “The place of super edge-magic labelings among otherclasses of labelings,” Discrete Mathematics, vol. 231, no. 1-3, pp.153–168, 2001.

Page 7: New Results on the (Super) Edge-Magic Deficiency of Chain ...downloads.hindawi.com/journals/ijmms/2017/5156974.pdf · magic deficiency of a graph. They define theedge-magic deficiencyof

Submit your manuscripts athttps://www.hindawi.com

Hindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

MathematicsJournal of

Hindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

Mathematical Problems in Engineering

Hindawi Publishing Corporationhttp://www.hindawi.com

Differential EquationsInternational Journal of

Volume 2014

Applied MathematicsJournal of

Hindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

Probability and StatisticsHindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

Journal of

Hindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

Mathematical PhysicsAdvances in

Complex AnalysisJournal of

Hindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

OptimizationJournal of

Hindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

CombinatoricsHindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

International Journal of

Hindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

Operations ResearchAdvances in

Journal of

Hindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

Function Spaces

Abstract and Applied AnalysisHindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

International Journal of Mathematics and Mathematical Sciences

Hindawi Publishing Corporationhttp://www.hindawi.com Volume 201

The Scientific World JournalHindawi Publishing Corporation http://www.hindawi.com Volume 2014

Hindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

Algebra

Discrete Dynamics in Nature and Society

Hindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

Hindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

Decision SciencesAdvances in

Journal of

Hindawi Publishing Corporationhttp://www.hindawi.com

Volume 2014 Hindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

Stochastic AnalysisInternational Journal of