• Tidak ada hasil yang ditemukan

(Similarity + Document) Star metric dimension of complete, bipartite, complete bipartite and fan graphs

N/A
N/A
Protected

Academic year: 2023

Membagikan "(Similarity + Document) Star metric dimension of complete, bipartite, complete bipartite and fan graphs"

Copied!
7
0
0

Teks penuh

(1)

International Journal of Trends in Mathematics Education Research Vol. 5, No. 2 (2022), pp. 199-205

ISSN 2621-8488 (online)

DOI: https://doi.org/10.33122/ijtmer.v5i2.137

Research Article

Star metric dimension of complete, bipartite, complete bipartite and fan graphs

Reni Umilasari1๏€ช, Ilham Saifudin1 & Isnawati Lujeng Lestari2

1 Department of Informatics Engineering, Universitas Muhammadiyah Jember, Jawa Timur, Indonesia, 68121

2 Department of Mathematics Education, Institut Teknologi dan Sains Nahdlatul Ulama Pasuruan, Jawa Timur, Indonesia, 67171

๏€ชCorresponding Author: [email protected] | Phone Number [+6285233372027]

Received: 10 March 2022 Revised: 22 April 2022 Accepted: 24 May 2022 Available online: 30 June 2022

1. INTRODUCTION

The graph theory was first introduced by Leonhard Euler in 1736 with the case of the Konisberg Bridge. The problem that arises is known as the Konisberg bridge mystery, namely how to cross the four landmasses by crossing the seven bridges exactly once. To analyze the problem of the Konisberg bridge, Euler presents the land as a vertex while the bridge is presented as an edge. Euler argued that it was impossible for a person to cross each of the seven bridges exactly once. The proof is suspected to be the beginning of the emergence of the concept of graph (Kuziak et al., 2017). One of some topics in graph theory that is interesting and developed continuously is metric dimension. The theory of metric dimension was firstly proposed by Harary and Melter in 1976. The concept can be utilized to distuingish each vertex in a connected graph G by determining its representation with respect to subset of vertex set of G (Saputro et al., 2017). To get some new well known graph, some researcher introduced operation of some classes of graphs. Then, metric dimension of corona product graphs was been researched by (Yero et al., 2011).

Another operation is strong product graphs. Fernau H and Rodrรญguez-Velรกzquez J investigate the adjacency metric dimension of corona and strong product graphs. The results of their research are about the computational and combinatorial property. In 2018 Gonzรกlez A, Hernando C, and Mora M make a new definition related to the metric dimension and dominating set. They called the concept by Metric-locating-dominating sets. A dominating set of any graph is said to be a metric-locating-dominating set if the distance of each elements dominating set to another vertex of the graph is different.

Another concept development of metric dimension was done by some researcher such as strong metric dimension by (Kuziak et al., 2013) and they can compute the metric dimension by the subgraph (Kuziak et al., 2017) and they continue for the next year to get the properties of strong resolving graphs (Kuziak et al., 2018). Next, strong metric dimension was modified as the fractional strong metric dimension (Kang et al., 2018).

Another concept that related to metric dimension is star metric dimension which was firstly proposed by Mutia, N., 2015.

(Mutianingsih et al., 2016). They defined the star metric dimension and determine the star metric dimension of wheel- similar graph. The order set of ๐‘ = {๐‘ง1, ๐‘ง2, โ€ฆ , ๐‘ง๐‘›} โІ ๐‘‰(๐บ) called star resolving set of connected graph ๐บ if ๐‘ is Star Graph and for every vertex in G has different representation to the set ๐‘. The representation is expressed as the distance ๐‘‘(๐‘ข, ๐‘ง), it is the shortest path from vertex ๐‘ข to ๐‘ง for every ๐‘ข, ๐‘ง โˆˆ ๐‘‰(๐บ). Star resolving set with the minimum cardinality is called

ABSTRACT

One of the topics in graph theory that is interesting and developed continuously is metric dimension. It has some new variation concepts, such as star metric dimension. The order set of ๐‘ = {๐‘ง1, ๐‘ง2, โ€ฆ , ๐‘ง๐‘›} โІ ๐‘‰(๐บ) called star resolving set of connected graph ๐บ if ๐‘ is Star Graph and for every vertex in G has different representation to the set ๐‘. The representation is expressed as the distance ๐‘‘(๐‘ข, ๐‘ง), it is the shortest path from vertex ๐‘ข to ๐‘ง for every ๐‘ข, ๐‘ง โˆˆ ๐‘‰(๐บ). Star basis of a graph is the smallest cardinality of star resolving set. The number of vertex in star basis is called star metric dimension of ๐บ which denoted by ๐‘†๐‘‘๐‘–๐‘š(๐บ). The purpose of this article is to determine the characteristic of star metric dimension and the value of star metric dimension of some classes of graphs. The method which is used in this study is library research. Some of the results of this research are complete graph has ๐‘†๐‘‘๐‘–๐‘š(๐พ๐‘›) = ๐‘› โˆ’ 1, for ๐‘› โ‰ฅ 3, bipartite graph ๐พ2,๐‘› has ๐‘†๐‘‘๐‘–๐‘š (๐พ2,๐‘›) = ๐‘›, for ๐‘› โ‰ฅ 3. Besides complete bipartite graph hasnโ€™t star metric dimension or for ๐‘š, ๐‘› โ‰ฅ 3 or it can said that ๐‘†๐‘‘๐‘–๐‘š (๐พ๐‘š,๐‘›) = 0. Another graph, that is Fan graph has ๐‘†๐‘‘๐‘–๐‘š (๐น๐‘›) = 2 for 2 โ‰ค ๐‘› โ‰ค 5 and for ๐‘› โ‰ฅ 6 ๐‘†๐‘‘๐‘–๐‘š (๐น๐‘›) = โŒˆ2๐‘›+3

5 โŒ‰.

Keywords: Metric Dimension; Star Basis; Star Metric Dimension; Star Resolving Set; Complete Bipartite

(2)

200

star basis and its cardinality is called star metric dimension of ๐บ is ๐‘†๐‘‘๐‘–๐‘š(๐บ) (Mutia, 2015).

Figure 1. Star Graph (๐‘บ๐Ÿ’) with ๐’…๐’Š๐’Ž(๐‘บ๐Ÿ’) = ๐Ÿ

Figure 2 shows a wheel graph (๐‘Š6) with the vertex set is ๐‘‰(๐‘Š6) = {๐‘œ, ๐‘Ž, ๐‘, ๐‘, ๐‘‘, ๐‘’, ๐‘“}, let the star resolving set is ๐‘ = {๐‘œ, ๐‘Ž, ๐‘}.

The representation every vertex of ๐‘‰(๐‘Š6) to ๐‘ are:

๐‘Ÿ(๐‘œ|๐‘) = {0,1,1}

๐‘Ÿ(๐‘Ž|๐‘) = {1,1,1}

๐‘Ÿ(๐‘|๐‘) = {1,1,0}

๐‘Ÿ(๐‘|๐‘) = {1,2,1}

๐‘Ÿ(๐‘‘|๐‘) = {1,2,2}

๐‘Ÿ(๐‘’|๐‘) = {1,1,2}

๐‘Ÿ(๐‘“|๐‘) = {1,0,2}

We can see that every vertex of ๐‘‰(๐‘Š6) has different representation to ๐‘, then Z is star resolving set of ๐‘Š6. Besides the Figure 3 show that if we take |๐‘| = 2, and suppose ๐‘ = {๐‘œ, ๐‘“}. Then, there are some vertices have same representation to ๐‘, for example ๐‘Ÿ(๐‘Ž|๐‘) = {1,1} = ๐‘Ÿ(๐‘’|๐‘) = {1,1}. Thus ๐‘ = {๐‘œ, ๐‘“} is not star resolving set of ๐‘Š6. Therefore |๐‘| = 3 is star resolving set with minimum cardinality. The formal proof of star metric dimension of wheel graph has been found by (Mutia, 2015) as presented in Theorem 1. While Theorem 2 describe the star metric dimension of gear graph.

Figure 2. Wheel graph (๐‘พ๐Ÿ”) with star resolving set equals three

Figure 3. Wheel graph (๐‘พ๐Ÿ”)

Theorem 1. If ๐‘Š๐‘› is wheel graph with the order ๐‘› + 1 and ๐‘› โ‰ฅ 7, then star metric dimension ๐‘ ๐‘‘๐‘–๐‘š(๐‘Š๐‘›) = โŒˆ๐‘›

2โŒ‰. (Mutia, 2015) Theorem 2. If ๐บ2๐‘›is gir graph with the order order 2๐‘› + 1 and ๐‘› โ‰ฅ 5, then star metric dimension ๐‘ ๐‘‘๐‘–๐‘š(๐บ2๐‘›) = ๐‘›. (Mutia, 2015)

Since the concept of star metric dimension is interesting to be developed because it still can be development with some classes of graph. The topic of star metric dimension is interesting. (Saifudin et al., 2021) succeed found the application of this topic to real life problem. They determined the aircraft navigation to protect a forest fire area by using the concept of star metric dimension. This topic still needed to be developed for any single graph or some products of graphs and some characteristic of star metric dimension not submitted yet. Therefore, in this paper we present some of characterization of star metric dimension and determine the star metric dimension of some special graph.

(3)

2. RESEARCH METHOD

The method which is used in this study are pattern recognition and axiomatic deductive methods. All the procedures are given below:

1) Reviewing the literature related to the concept of graph and star metric dimension.

2) Observing star metric dimension of some well know graphs.

3) Determining star metric dimension (๐‘†๐‘‘๐‘–๐‘š) of graphs based on the procedure below:

a) Determining the candidates of star local resolving set ๐‘ starting for the smallest cardinality

b) If ๐‘ is Star Graph and for every vertex in G has different representation to the set ๐‘. The representation is expressed as the distance ๐‘‘(๐‘ข, ๐‘ง), it is the shortest path from vertex ๐‘ข to ๐‘ง for every ๐‘ข, ๐‘ง โˆˆ ๐‘‰(๐บ).

c) Verifying representation of each vertex ๐‘ข element ๐บ to local resolving set ๐‘ starting for the smallest cardinality.

d) If the representation of each adjacent vertex to ๐‘ is different, then ๐‘†๐‘‘๐‘–๐‘š(๐บ) = |๐‘|, if it is not, then repeat all steps until the biggest cardinality of ๐‘.

3. RESULTS AND DISCUSSION

The following lemma and theorem shows the new results of star metric dimensions, starting with the characteristics of the star metric dimensions, then star metric dimensions on special graphs, i.e. complete, complete bipartite and fan graph:

Lemma 3. If ๐บ be a connected graph, ๐‘‡ โІ ๐‘‰(๐บ), ๐‘‡ consist of star resolving set of graph ๐บ and ๐‘‡ form a star graph, then ๐‘‡ is star metric dimension of ๐บ.

Proof. Let ๐‘ = {๐‘ข๐‘–|๐‘– = 1,2, โ€ฆ , ๐‘˜} โІ ๐‘‰(๐บ) is star resolving set of graph ๐บ and ๐‘‡ โІ ๐‘‰(๐บ). Let ๐‘ โІ ๐‘‡, because ๐‘ star resolving set, for every ๐‘ข, ๐‘ฃ โˆˆ ๐‘‰(๐บ) then ๐‘Ÿ(๐‘ข|๐‘) โ‰  ๐‘Ÿ(๐‘ฃ|๐‘) and ๐‘Ÿ(๐‘ข|๐‘‡) โ‰  ๐‘Ÿ(๐‘ฃ|๐‘‡) because ๐‘ โІ ๐‘‡. Next, because ๐‘‡ form star graph, then ๐‘‡ is star resolving set of graph ๐บ.โˆŽ

Lemma 4. If ๐บ be a connected graph, ๐‘ โІ ๐‘‰(๐บ) and For every ๐‘ฃ๐‘–, ๐‘ฃ๐‘—โˆˆ ๐‘ then ๐‘Ÿ(๐‘ฃ๐‘–|๐‘) โ‰  ๐‘Ÿ(๐‘ฃ๐‘—|๐‘).

Proof. Let ๐‘ = {๐‘ฃ1, ๐‘ฃ2, ๐‘ฃ3, โ€ฆ , ๐‘ฃ๐‘˜} โІ ๐‘‰(๐บ). Because for every ๐‘ฃ๐‘–, ๐‘ฃ๐‘—โˆˆ ๐‘ with ๐‘– โ‰  ๐‘— then ๐‘‘(๐‘ฃ๐‘–, ๐‘ฃ๐‘–) = 0 and ๐‘‘(๐‘ฃ๐‘–, ๐‘ฃ๐‘—) โ‰  0, then there exist 0 of ith element in ๐‘Ÿ(๐‘ฃ๐‘–|๐‘) for every ๐‘ฃ๐‘–โˆˆ ๐‘. As a result ๐‘Ÿ(๐‘ฃ๐‘–|๐‘Š๐‘™) โ‰  ๐‘Ÿ(๐‘ฃ๐‘—|๐‘Š๐‘™) for ๐‘– โ‰  ๐‘—. โˆŽ

Theorem 5. If ๐‘› โ‰ฅ 3, then ๐‘†๐‘‘๐‘–๐‘š(๐พ๐‘›) = ๐‘› โˆ’ 1.

Proof. Let ๐‘‰(๐พ๐‘›) = {๐‘ฃ๐‘–|๐‘– = 1,2,3, โ€ฆ , ๐‘› }and๐ธ(๐พ๐‘›) = {๐‘ฃ๐‘–๐‘ฃ๐‘—|๐‘–, ๐‘— = 1,2,3, โ€ฆ , ๐‘›, ๐‘– โ‰  ๐‘—}with ๐‘› โ‰ฅ 3. Choose ๐‘ = {๐‘ฃ๐‘–|๐‘– = 1,2,3, โ€ฆ , ๐‘› โˆ’ 1} then |๐‘| = ๐‘› โˆ’ 1. See at Lemma 4, we get ๐‘Ÿ(๐‘ฃ๐‘–|๐‘) โ‰  ๐‘Ÿ(๐‘ฃ๐‘—|๐‘) for every ๐‘ฃ๐‘–, ๐‘ฃ๐‘—โˆˆ ๐‘ with ๐‘– โ‰  ๐‘—. Then, because ๐‘Ÿ(๐‘ฃ๐‘›|๐‘) =

(1,1,1,1, โ€ฆ ,1โŸ

(๐‘›โˆ’1)โˆ’๐‘ก๐‘ข๐‘๐‘™๐‘’

), so ๐‘Š is resolving set of graph ๐พ๐‘›. In other side, because for every ๐‘ฃ๐‘–โˆˆ ๐‘ with ๐‘– = 2,3,4, โ€ฆ , ๐‘› โˆ’ 1 then ๐‘ฃ1๐‘ฃ๐‘–โˆˆ

๐ธ(๐พ๐‘›), thus ๐‘ form star graph ๐พ1,๐‘›โˆ’2 then ๐‘ is star resolving set of graph ๐พ๐‘›. Next, because ๐‘‘๐‘–๐‘š (๐พ๐‘›) = ๐‘› โˆ’ 1, it clearly that ๐‘ is star metric dimension with minimum cardinality then it can conclude that ๐‘†๐‘‘๐‘–๐‘š(๐พ๐‘›) = ๐‘› โˆ’ 1. โˆŽ

Theorem 6. If ๐‘› โ‰ฅ 2, then ๐‘†๐‘‘๐‘–๐‘š (๐พ2,๐‘›) = ๐‘›.

Proof. Let ๐‘‰ (๐พ2,๐‘›) = {๐‘Ž1, ๐‘Ž2, ๐‘๐‘–|๐‘– = 1,2, โ€ฆ , ๐‘›} and ๐ธ (๐พ2,๐‘›) = {๐‘Ž1๐‘๐‘–, ๐‘Ž2๐‘๐‘– |๐‘– = 1,2,3, โ€ฆ , ๐‘›}. Choose ๐‘ = {๐‘Ž1, ๐‘๐‘–|๐‘– = 1,2,3, โ€ฆ , ๐‘› โˆ’ 1}

then |๐‘| = ๐‘›. See at Lemma 4, we have ๐‘Ÿ (๐‘Ž1|๐‘) โ‰  ๐‘Ÿ(๐‘๐‘–|๐‘) and ๐‘Ÿ(๐‘๐‘—|๐‘) โ‰  ๐‘Ÿ(๐‘๐‘˜|๐‘) for every ๐‘Ž1, ๐‘๐‘–, ๐‘๐‘—, ๐‘๐‘˜ โˆˆ ๐‘ with ๐‘— โ‰  ๐‘˜.

Then, because ๐‘Ÿ (๐‘Ž2|๐‘) = (2, 1,1,1, โ€ฆ ,1โŸ

(๐‘›โˆ’1)โˆ’๐‘ก๐‘ข๐‘๐‘™๐‘’

) and ๐‘Ÿ(๐‘๐‘›|๐‘) = (1, 2,2,2, โ€ฆ ,2โŸ

(๐‘›โˆ’1)โˆ’๐‘ก๐‘ข๐‘๐‘™๐‘’

), thus ๐‘ is resolving set of ๐พ2,๐‘›. In other side, because

for every ๐‘๐‘–โˆˆ ๐‘ with ๐‘– = 1,2,3, โ€ฆ , ๐‘› โˆ’ 1 then ๐‘Ž1๐‘๐‘–โˆˆ ๐ธ(๐พ2,๐‘›), hence ๐‘ form star graph ๐พ1,๐‘›โˆ’1 then ๐‘ is star resolving set of ๐พ2,๐‘›. Next, because ๐‘‘๐‘–๐‘š (๐พ2,๐‘›) = ๐‘›, it clearly that ๐‘ is star resolving set with minimum cardinality. Therefore we can

conclude that ๐‘†๐‘‘๐‘–๐‘š (๐พ2,๐‘›) = ๐‘›. โˆŽ

Theorem 7. If ๐‘š, ๐‘› โ‰ฅ 3, then ๐‘†๐‘‘๐‘–๐‘š (๐พ๐‘š,๐‘›) = 0.

Proof. Let ๐‘‰(๐พ๐‘š,๐‘›) = {๐‘Ž๐‘–|๐‘– = 1,2,3, โ€ฆ , ๐‘š} โˆช { ๐‘๐‘—|๐‘— = 1,2, โ€ฆ , ๐‘›}and๐ธ(๐พ๐‘š,๐‘›) = {๐‘Ž๐‘–๐‘๐‘—|๐‘– = 1,2,3, โ€ฆ , ๐‘š ; ๐‘— = 1,2,3, โ€ฆ , ๐‘›}with ๐‘š, ๐‘› โ‰ฅ 3.

Since ๐พ๐‘š,๐‘› is a complete bipartite graph, then there exist two possibilities for ๐‘:

(4)

202

1. Select ๐‘ = {๐‘Ž๐‘–|๐‘– = 2,3,4, โ€ฆ , ๐‘š} โˆช {๐‘๐‘—|๐‘— = 2,3,4, โ€ฆ , ๐‘›}, so that |๐‘| = ๐‘š + ๐‘› โˆ’ 2. Based on Lemma 4, we get that ๐‘Ÿ(๐‘ข|๐‘) โ‰ 

๐‘Ÿ(๐‘ฃ|๐‘) for every ๐‘ข, ๐‘ฃ โˆˆ ๐‘ with ๐‘ข โ‰  ๐‘ฃ . Furthermore, Since ๐‘Ÿ (๐‘Ž1|๐‘) = ( 2,2,2, โ€ฆ ,2โŸ

(๐‘šโˆ’1)โˆ’๐‘ก๐‘ข๐‘๐‘™๐‘’

, 1,1,1, โ€ฆ ,1โŸ

(๐‘›โˆ’1)โˆ’๐‘ก๐‘ข๐‘๐‘™๐‘’

) and ๐‘Ÿ (๐‘1|๐‘) =

( 1,1,1, โ€ฆ ,1โŸ

(๐‘šโˆ’1)โˆ’๐‘ก๐‘ข๐‘๐‘™๐‘’

, 2,2,2, โ€ฆ ,2โŸ

(๐‘›โˆ’1)โˆ’๐‘ก๐‘ข๐‘๐‘™๐‘’

), then ๐‘Š is resolving set of ๐พ๐‘š,๐‘›. Furthermore, Since ๐‘ doesnโ€™t form a star, then ๐‘ is not a

star resolving set of ๐พ๐‘š,๐‘›.

2. Select ๐‘ = {๐‘Ž1, ๐‘1} so that |๐‘| = 2. Since ๐‘‘๐‘–๐‘š (๐พ๐‘š,๐‘›) = ๐‘š + ๐‘› โˆ’ 2, it clearly shows that ๐‘ is not a resolving set of ๐พ๐‘š,๐‘› so that ๐‘ is not a star resolving set of ๐พ๐‘š,๐‘›.

Furthermore, Since ๐‘‘๐‘–๐‘š (๐พ๐‘š,๐‘›) = ๐‘š + ๐‘› โˆ’ 2, then ๐‘†๐‘‘๐‘–๐‘š (๐พ๐‘š,๐‘›) โ‰ฅ ๐‘š + ๐‘› โˆ’ 2. On the other hand, Since star subgraph of ๐พ๐‘š,๐‘› only can be obtained by ๐‘š + 1 or ๐‘› + 1 vertices, then ๐‘†๐‘‘๐‘–๐‘š (๐พ๐‘š,๐‘›) โ‰ค ๐‘š + 1 or ๐‘†๐‘‘๐‘–๐‘š (๐พ๐‘š,๐‘›) โ‰ค ๐‘› + 1. Contradiction with the fact that ๐‘†๐‘‘๐‘–๐‘š (๐พ๐‘š,๐‘›) โ‰ฅ ๐‘š + ๐‘› โˆ’ 2. Consequently, there is no vertex set as star resolving set of ๐พ๐‘š,๐‘› so that ๐‘†๐‘‘๐‘–๐‘š (๐พ๐‘š,๐‘›) = 0. โˆŽ

Theorem 8. If 2 โ‰ค ๐‘› โ‰ค 5, then ๐‘†๐‘‘๐‘–๐‘š (๐น๐‘›) = 2.

Proof. Let ๐‘‰(๐น๐‘›) = {๐‘ฃ, ๐‘ฃ๐‘–|๐‘– = 1,2, โ€ฆ , ๐‘›} and ๐ธ(๐น๐‘›) = {๐‘ฃ๐‘ฃ๐‘–|๐‘– = 1,2, โ€ฆ , ๐‘›} โˆช {๐‘ฃ๐‘—๐‘ฃ๐‘—+1|๐‘— = 1,2, โ€ฆ , ๐‘› โˆ’ 1}. There are for cases for ๐‘›:

1. For ๐‘› = 2, select ๐‘ = {๐‘ฃ, ๐‘ฃ1} so that |๐‘| = 2. Since ๐‘Ÿ(๐‘ฃ|๐‘) = (0,1), ๐‘Ÿ (๐‘ฃ1|๐‘) = (1,0) and ๐‘Ÿ (๐‘ฃ2|๐‘) = (1,1), then ๐‘ is a resolving set of ๐น2. While, since ๐‘ forms ๐พ1,1 star, then ๐‘ is a star resolving set of ๐น2. Next, take any singleton. Let

๐‘‡ = {๐‘ฃ}, then we get ๐‘Ÿ (๐‘ฃ1|๐‘‡) = ๐‘Ÿ (๐‘ฃ2|๐‘‡) = (1,1) so that ๐‘‡ is not a resolving set of ๐น2. Consequently, ๐‘‡ is not a resolving

set of ๐น2. So that, ๐‘ is star resolving set with minimum cardinality and ๐‘†๐‘‘๐‘–๐‘š (๐น2) = 2.

2. For ๐‘› = 3, select ๐‘ = {๐‘ฃ1, ๐‘ฃ2} so that |๐‘| = 2. Since ๐‘Ÿ(๐‘ฃ|๐‘) = (1,1) , ๐‘Ÿ (๐‘ฃ1|๐‘) = (0,1) , ๐‘Ÿ (๐‘ฃ2|๐‘) = (1,0) and ๐‘Ÿ (๐‘ฃ3|๐‘) = (2,1), then ๐‘ is a resolving set of ๐น3. While, since ๐‘ forms a ๐พ1,1, then ๐‘ is star resolving set of ๐น3. Next, take any singleton. There are two possibilities: (i) ๐‘ฃ with deg(๐‘ฃ) = 2; or (ii) ๐‘ฃ with deg(๐‘ฃ) = 3.

(i) Let ๐‘‡ = {๐‘ฃ1}, then we get ๐‘Ÿ(๐‘ฃ|๐‘‡) = ๐‘Ÿ (๐‘ฃ2|๐‘‡) = (1) so that ๐‘‡ is not a resolving set of ๐น3. Consequently, ๐‘‡ is not a resolving set of ๐น3.

(ii) Let ๐‘‡ = {๐‘ฃ}, then we get ๐‘Ÿ (๐‘ฃ1|๐‘‡) = ๐‘Ÿ (๐‘ฃ2|๐‘‡) = ๐‘Ÿ (๐‘ฃ3|๐‘‡) = (1) so that ๐‘‡ is not a resolving set of ๐น3. Consequently, ๐‘‡ is not a resolving set of ๐น3.

So that, ๐‘ is star resolving set with minimum cardinality and ๐‘†๐‘‘๐‘–๐‘š (๐น3) = 2.

3. For ๐‘› = 4, select ๐‘ = {๐‘ฃ2, ๐‘ฃ3} so that |๐‘| = 2. Since ๐‘Ÿ(๐‘ฃ|๐‘) = (1,1), ๐‘Ÿ (๐‘ฃ1|๐‘) = (1,2), ๐‘Ÿ (๐‘ฃ2|๐‘) = (0,1), ๐‘Ÿ (๐‘ฃ3|๐‘) = (1,0)

and ๐‘Ÿ (๐‘ฃ4|๐‘) = (2,1), then ๐‘ is a resolving set of ๐น4. While, since ๐‘ forms a ๐พ1,1, then ๐‘ is star resolving set of ๐น4. Next, take any singleton. There are two possibilities: (i) ๐‘ฃ with deg(๐‘ฃ) = 2; or (ii) ๐‘ฃ with deg(๐‘ฃ) = 3.

(i) Let ๐‘‡ = {๐‘ฃ1}, then we get ๐‘Ÿ(๐‘ฃ|๐‘‡) = ๐‘Ÿ (๐‘ฃ2|๐‘‡) = (1) so that ๐‘‡ is not a resolving set of ๐น4. Consequently, ๐‘‡ is not a resolving set of ๐น4.

(5)

(ii) Let ๐‘‡ = {๐‘ฃ} , then we get ๐‘Ÿ (๐‘ฃ1|๐‘‡) = ๐‘Ÿ (๐‘ฃ2|๐‘‡) = ๐‘Ÿ (๐‘ฃ3|๐‘‡) = ๐‘Ÿ (๐‘ฃ4|๐‘‡) = (1) so that ๐‘‡ is not a resolving set of ๐น4. Consequently, ๐‘‡ is not a resolving set of ๐น3.

So that, ๐‘ is a star resolving set with minimum cardinality and ๐‘†๐‘‘๐‘–๐‘š (๐น4) = 2.

4. For ๐‘› = 5, select ๐‘ = {๐‘ฃ2, ๐‘ฃ3} so that |๐‘| = 2. Since ๐‘Ÿ(๐‘ฃ|๐‘) = (1,1), ๐‘Ÿ (๐‘ฃ1|๐‘) = (1,2), ๐‘Ÿ (๐‘ฃ2|๐‘) = (0,1), ๐‘Ÿ (๐‘ฃ3|๐‘) = (1,0),

๐‘Ÿ (๐‘ฃ4|๐‘) = (2,1) and ๐‘Ÿ (๐‘ฃ5|๐‘) = (2,2), then ๐‘ is a resolving set of ๐น5. On the other hand, Since ๐‘ forms a ๐พ1,1, then ๐‘ is a star resolving set of ๐น5. Furthermore, take any singleton. There are two possibilities: (i) ๐‘ฃ with deg(๐‘ฃ) = 2; or (ii) ๐‘ฃ with deg(๐‘ฃ) = 3.

(i) Let ๐‘‡ = {๐‘ฃ1}, then we get ๐‘Ÿ(๐‘ฃ|๐‘‡) = ๐‘Ÿ (๐‘ฃ2|๐‘‡) = (1) so that ๐‘‡ is not a resolving set of ๐น5. Consequently, ๐‘‡ is not a resolving set of ๐น5.

(ii) Let ๐‘‡ = {๐‘ฃ}, then we get ๐‘Ÿ (๐‘ฃ1|๐‘‡) = ๐‘Ÿ (๐‘ฃ2|๐‘‡) = ๐‘Ÿ (๐‘ฃ3|๐‘‡) = ๐‘Ÿ (๐‘ฃ4|๐‘‡) = ๐‘Ÿ (๐‘ฃ5|๐‘‡) = (1) so that ๐‘‡ is not a resolving set of ๐น5. Consequently, ๐‘‡ is not a resolving set of ๐น5.

So that, ๐‘ is a star resolving set with minimum cardinality and ๐‘†๐‘‘๐‘–๐‘š (๐น5) = 2.

From the four possibilities above, we get that for ๐‘› = 2,3,4,5, ๐‘†๐‘‘๐‘–๐‘š(๐น๐‘›) = 2. โˆŽ Theorem 9. If ๐‘› โ‰ฅ 6, then ๐‘†๐‘‘๐‘–๐‘š (๐น๐‘›) = โŒˆ2๐‘›+3

5 โŒ‰.

Proof. Let ๐‘‰(๐น๐‘›) = {๐‘ฃ, ๐‘ฃ๐‘–|๐‘– = 1,2, โ€ฆ , ๐‘›} and ๐ธ(๐น๐‘›) = {๐‘ฃ๐‘ฃ๐‘–|๐‘– = 1,2, โ€ฆ , ๐‘›} โˆช {๐‘ฃ๐‘—๐‘ฃ๐‘—+1|๐‘— = 1,2, โ€ฆ , ๐‘› โˆ’ 1}. There are three cases for ๐‘›:

1. For ๐‘› โ‰ก 1 (๐‘š๐‘œ๐‘‘ 5) or ๐‘› โ‰ก 3 (๐‘š๐‘œ๐‘‘ 5) , select ๐‘ = {๐‘ฃ, ๐‘ฃ2, ๐‘ฃ4, ๐‘ฃ7, ๐‘ฃ9, โ€ฆ , ๐‘ฃ5๐‘–โˆ’3, ๐‘ฃ5๐‘–โˆ’1, โ€ฆ , ๐‘ฃ๐‘›โˆ’2} so that |๐‘| = โŒˆ2๐‘›+3

5 โŒ‰ . Based on Lemma 4, we get that ๐‘Ÿ(๐‘ข|๐‘) โ‰  ๐‘Ÿ(๐‘ฃ|๐‘) for every ๐‘ข, ๐‘ฃ โˆˆ ๐‘ with ๐‘ข โ‰  ๐‘ฃ. Furthermore, Since for every ๐‘ฃ๐‘–โˆˆ ๐‘‰(๐น๐‘›) we get:

๐‘Ÿ(๐‘ฃ๐‘–|๐‘) =

{

(

1,2,2,2, โ€ฆ ,2, 1โŸ

(๐‘– 3+1)๐‘กโ„Ž

, 2,2,2, โ€ฆ ,2 )

, ๐‘– โ‰ก 0 (๐‘š๐‘œ๐‘‘ 5)

(

1,2,2,2, โ€ฆ ,2, 1โŸ

(โŒˆ๐‘– 2โŒ‰โˆ’โŒŠ๐‘–

10โŒ‹+1)๐‘กโ„Ž

, 2,2,2, โ€ฆ ,2 )

, ๐‘– โ‰ก 1 (๐‘š๐‘œ๐‘‘ 5)

(

1,2,2,2, โ€ฆ ,2, 1โŸ

(โŒˆ๐‘– 3โŒ‰+โŒŠ๐‘–

15โŒ‹+1) ๐‘กโ„Ž

, 1โŸ

(โŒˆ๐‘– 3โŒ‰+โŒŠ๐‘–

15โŒ‹+2) ๐‘กโ„Ž

, 2,2,2, โ€ฆ ,2 )

, ๐‘– โ‰ก 3 (๐‘š๐‘œ๐‘‘ 5)

So that, ๐‘ is a resolving set of ๐น๐‘›. Furthermore, Since for every ๐‘ฃ5๐‘–โˆ’3, ๐‘ฃ5๐‘–โˆ’1โˆˆ ๐‘ we get ๐‘ฃ๐‘ฃ5๐‘–โˆ’3โˆˆ ๐ธ(๐น๐‘›) and ๐‘ฃ๐‘ฃ5๐‘–โˆ’1โˆˆ ๐ธ(๐น๐‘›), then ๐‘ forms a ๐พ

1,โŒˆ2๐‘›+3

5 โŒ‰โˆ’1 so that ๐‘ is a star resolving set of ๐น๐‘›. Furthermore, take any ๐‘‡ โІ ๐‘‰(๐น๐‘›) with |๐‘‡| < |๐‘|,

|๐‘‡| = |๐‘| โˆ’ 1. Then there are two cases for ๐‘‡:

(i) ๐‘‡ doesnโ€™t consist ๐‘ฃ. Let ๐‘‡ = {๐‘ฃ2, ๐‘ฃ4, ๐‘ฃ7, ๐‘ฃ9, โ€ฆ , ๐‘ฃ5๐‘–โˆ’3, ๐‘ฃ5๐‘–โˆ’1, โ€ฆ , ๐‘ฃ๐‘›โˆ’2}. Then ๐‘‡ doesnโ€™t form a star.

(ii) ๐‘‡ consists ๐‘ฃ. Let ๐‘‡ = {๐‘ฃ, ๐‘ฃ2, ๐‘ฃ4, ๐‘ฃ7, ๐‘ฃ9, โ€ฆ , ๐‘ฃ5๐‘–โˆ’3, ๐‘ฃ5๐‘–โˆ’1, โ€ฆ , ๐‘ฃ๐‘›โˆ’7}. There exist ๐‘ฃ๐‘›โˆ’2, ๐‘ฃ๐‘›โˆ’1, ๐‘ฃ๐‘›โˆˆ ๐‘‰(๐น๐‘›) โˆ’ ๐‘‡, so that ๐‘Ÿ(๐‘ฃ๐‘›โˆ’2|๐‘‡) = ๐‘Ÿ(๐‘ฃ๐‘›โˆ’1|๐‘‡) = ๐‘Ÿ(๐‘ฃ๐‘›|๐‘‡) = (2,2,2, โ€ฆ ,2). Consequently, ๐‘‡ is not a resolving set of ๐น๐‘›.

So that, there is no star resolving set with cardinality less then |๐‘| so that ๐‘ is a star resolving set with minimum cardinality and ๐‘†๐‘‘๐‘–๐‘š (๐น๐‘›) = โŒˆ2๐‘›+3

5 โŒ‰ For ๐‘› โ‰ก 1 (๐‘š๐‘œ๐‘‘ 5) or ๐‘› โ‰ก 3 (๐‘š๐‘œ๐‘‘ 5).

(6)

204

2. For ๐‘› โ‰ก 2 (๐‘š๐‘œ๐‘‘ 5) or ๐‘› โ‰ก 4 (๐‘š๐‘œ๐‘‘ 5) , select ๐‘ = {๐‘ฃ, ๐‘ฃ2, ๐‘ฃ4, ๐‘ฃ7, ๐‘ฃ9, โ€ฆ , ๐‘ฃ5๐‘–โˆ’3, ๐‘ฃ5๐‘–โˆ’1, โ€ฆ , ๐‘ฃ๐‘›} so that |๐‘| = โŒˆ2๐‘›+3

5 โŒ‰ . Based on Lemma 4, we get that ๐‘Ÿ(๐‘ข|๐‘) โ‰  ๐‘Ÿ(๐‘ฃ|๐‘) for every ๐‘ข, ๐‘ฃ โˆˆ ๐‘ with ๐‘ข โ‰  ๐‘ฃ. Furthermore, Since for every ๐‘ฃ๐‘–โˆˆ ๐‘‰(๐น๐‘›) we get:

๐‘Ÿ(๐‘ฃ๐‘–|๐‘) =

{

(

1,2,2,2, โ€ฆ ,2, 1โŸ

(๐‘– 3+1)

๐‘กโ„Ž

, 2,2,2, โ€ฆ ,2 )

, ๐‘– โ‰ก 0 (๐‘š๐‘œ๐‘‘ 5)

(

1,2,2,2, โ€ฆ ,2, 1โŸ

(โŒˆ๐‘– 2โŒ‰โˆ’โŒŠ๐‘–

10โŒ‹+1) ๐‘กโ„Ž

, 2,2,2, โ€ฆ ,2 )

, ๐‘– โ‰ก 1 (๐‘š๐‘œ๐‘‘ 5)

(

1,2,2,2, โ€ฆ ,2, 1โŸ

(โŒˆ๐‘– 3โŒ‰+โŒŠ๐‘–

15โŒ‹+1)๐‘กโ„Ž

, 1โŸ

(โŒˆ๐‘– 3โŒ‰+โŒŠ๐‘–

15โŒ‹+2)๐‘กโ„Ž

, 2,2,2, โ€ฆ ,2 )

, ๐‘– โ‰ก 3 (๐‘š๐‘œ๐‘‘ 5)

So that, ๐‘ is a resolving set of ๐น๐‘›. Furthermore, Since for every ๐‘ฃ5๐‘–โˆ’3, ๐‘ฃ5๐‘–โˆ’1โˆˆ ๐‘ we get ๐‘ฃ๐‘ฃ5๐‘–โˆ’3โˆˆ ๐ธ(๐น๐‘›) and ๐‘ฃ๐‘ฃ5๐‘–โˆ’1โˆˆ ๐ธ(๐น๐‘›), then ๐‘ forms a ๐พ

1,โŒˆ2๐‘›+3

5 โŒ‰โˆ’1 so that ๐‘ is a star resolving set of ๐น๐‘›. Furthermore, take any ๐‘‡ โІ ๐‘‰(๐น๐‘›) with |๐‘‡| < |๐‘|,

|๐‘‡| = |๐‘| โˆ’ 1. Then there are two cases for ๐‘‡:

(i) ๐‘‡ doesnโ€™t consist ๐‘ฃ. Let ๐‘‡ = {๐‘ฃ2, ๐‘ฃ4, ๐‘ฃ7, ๐‘ฃ9, โ€ฆ , ๐‘ฃ5๐‘–โˆ’3, ๐‘ฃ5๐‘–โˆ’1, โ€ฆ , ๐‘ฃ๐‘›}. Then ๐‘‡ doesnโ€™t form a star.

(ii) ๐‘‡ consists ๐‘ฃ . Let ๐‘‡ = {๐‘ฃ, ๐‘ฃ2, ๐‘ฃ4, ๐‘ฃ7, ๐‘ฃ9, โ€ฆ , ๐‘ฃ5๐‘–โˆ’3, ๐‘ฃ5๐‘–โˆ’1, โ€ฆ , ๐‘ฃ๐‘›โˆ’5}. There exists ๐‘ฃ๐‘›โˆ’2, ๐‘ฃ๐‘›โˆ’1, ๐‘ฃ๐‘›โˆˆ ๐‘‰(๐น๐‘›) โˆ’ ๐‘‡ , so that ๐‘Ÿ(๐‘ฃ๐‘›โˆ’2|๐‘‡) = ๐‘Ÿ(๐‘ฃ๐‘›โˆ’1|๐‘‡) = ๐‘Ÿ(๐‘ฃ๐‘›|๐‘‡) = (2,2,2, โ€ฆ ,2). Consequently, ๐‘‡ is not a resolving set of ๐น๐‘›.

So that, there is no star resolving set with cardinality less then |๐‘| so that ๐‘ is a star resolving set with minimum cardinality and ๐‘†๐‘‘๐‘–๐‘š (๐น๐‘›) = โŒˆ2๐‘›+3

5 โŒ‰ For ๐‘› โ‰ก 2 (๐‘š๐‘œ๐‘‘ 5) or ๐‘› โ‰ก 4 (๐‘š๐‘œ๐‘‘ 5).

3. For ๐‘› โ‰ก 0 (๐‘š๐‘œ๐‘‘ 5), select ๐‘ = {๐‘ฃ, ๐‘ฃ2, ๐‘ฃ4, ๐‘ฃ7, ๐‘ฃ9, โ€ฆ , ๐‘ฃ5๐‘–โˆ’3, ๐‘ฃ5๐‘–โˆ’1, โ€ฆ , ๐‘ฃ๐‘›โˆ’1} so that |๐‘| = โŒˆ2๐‘›+3

5 โŒ‰. Based on Lemma 4, we get that ๐‘Ÿ(๐‘ข|๐‘) โ‰  ๐‘Ÿ(๐‘ฃ|๐‘) for every ๐‘ข, ๐‘ฃ โˆˆ ๐‘ with ๐‘ข โ‰  ๐‘ฃ. Furthermore, Since for every ๐‘ฃ๐‘–โˆˆ ๐‘‰(๐น๐‘›) we get:

๐‘Ÿ(๐‘ฃ๐‘–|๐‘) =

{

(

1,2,2,2, โ€ฆ ,2, 1โŸ

(๐‘– 3+1)

๐‘กโ„Ž

, 2,2,2, โ€ฆ ,2 )

, ๐‘– โ‰ก 0 (๐‘š๐‘œ๐‘‘ 5)

(

1,2,2,2, โ€ฆ ,2, 1โŸ

(โŒˆ๐‘– 2โŒ‰โˆ’โŒŠ๐‘–

10โŒ‹+1) ๐‘กโ„Ž

, 2,2,2, โ€ฆ ,2 )

, ๐‘– โ‰ก 1 (๐‘š๐‘œ๐‘‘ 5)

(

1,2,2,2, โ€ฆ ,2, 1โŸ

(โŒˆ๐‘– 3โŒ‰+โŒŠ๐‘–

15โŒ‹+1)๐‘กโ„Ž

, 1โŸ

(โŒˆ๐‘– 3โŒ‰+โŒŠ๐‘–

15โŒ‹+2)๐‘กโ„Ž

, 2,2,2, โ€ฆ ,2 )

, ๐‘– โ‰ก 3 (๐‘š๐‘œ๐‘‘ 5)

So that, ๐‘ is a resolving set of ๐น๐‘›. Furthermore, Since for every ๐‘ฃ5๐‘–โˆ’3, ๐‘ฃ5๐‘–โˆ’1โˆˆ ๐‘ we get ๐‘ฃ๐‘ฃ5๐‘–โˆ’3โˆˆ ๐ธ(๐น๐‘›) and ๐‘ฃ๐‘ฃ5๐‘–โˆ’1โˆˆ ๐ธ(๐น๐‘›), then ๐‘ forms a ๐พ

1,โŒˆ2๐‘›+3

5 โŒ‰โˆ’1 so that ๐‘ is a star resolving set of ๐น๐‘›. Furthermore, take any ๐‘‡ โІ ๐‘‰(๐น๐‘›) with |๐‘‡| < |๐‘|,

|๐‘‡| = |๐‘| โˆ’ 1. Then there are two cases for ๐‘‡:

(iii) ๐‘‡ doesnโ€™t consist ๐‘ฃ. Let ๐‘‡ = {๐‘ฃ2, ๐‘ฃ4, ๐‘ฃ7, ๐‘ฃ9, โ€ฆ , ๐‘ฃ5๐‘–โˆ’3, ๐‘ฃ5๐‘–โˆ’1, โ€ฆ , ๐‘ฃ๐‘›โˆ’1}. Then ๐‘‡ doesnโ€™t form a star.

(iv) ๐‘‡ consist ๐‘ฃ . Let ๐‘‡ = {๐‘ฃ, ๐‘ฃ2, ๐‘ฃ4, ๐‘ฃ7, ๐‘ฃ9, โ€ฆ , ๐‘ฃ5๐‘–โˆ’3, ๐‘ฃ5๐‘–โˆ’1, โ€ฆ , ๐‘ฃ๐‘›โˆ’6}. There exists ๐‘ฃ๐‘›โˆ’2, ๐‘ฃ๐‘›โˆ’1, ๐‘ฃ๐‘›โˆˆ ๐‘‰(๐น๐‘›) โˆ’ ๐‘‡ , so that ๐‘Ÿ(๐‘ฃ๐‘›โˆ’2|๐‘‡) = ๐‘Ÿ(๐‘ฃ๐‘›โˆ’1|๐‘‡) = ๐‘Ÿ(๐‘ฃ๐‘›|๐‘‡) = (2,2,2, โ€ฆ ,2). Consequently, ๐‘‡ is not a resolving set of ๐น๐‘›.

So that, there is no star resolving set with cardinality less then |๐‘| so that ๐‘ is a star resolving set with minimum cardinality and ๐‘†๐‘‘๐‘–๐‘š (๐น๐‘›) = โŒˆ2๐‘›+3

5 โŒ‰ For ๐‘› โ‰ก 0 (๐‘š๐‘œ๐‘‘ 5) or ๐‘› โ‰ก 3 (๐‘š๐‘œ๐‘‘ 5).

(7)

Based on three cases above, we get that for ๐‘› โ‰ฅ 6 we get ๐‘†๐‘‘๐‘–๐‘š(๐น๐‘›) = โŒˆ2๐‘›+3

5 โŒ‰. โˆŽ

4. CONCLUSION

Based on the all the explanations above, we can conclude that complete graph has ๐‘บ๐’…๐’Š๐’Ž(๐‘ฒ๐’) = ๐’ โˆ’ ๐Ÿ, for ๐’ โ‰ฅ ๐Ÿ‘, bipartite graph ๐‘ฒ๐Ÿ,๐’ has ๐‘บ๐’…๐’Š๐’Ž (๐‘ฒ๐Ÿ,๐’) = ๐’, for ๐’ โ‰ฅ ๐Ÿ‘. Besides complete bipartite graph hasnโ€™t star metric dimension or for ๐’Ž, ๐’ โ‰ฅ ๐Ÿ‘ or it can said that ๐‘บ๐’…๐’Š๐’Ž (๐‘ฒ๐’Ž,๐’) = ๐ŸŽ. Another graph, that is Fan graph has ๐‘บ๐’…๐’Š๐’Ž (๐‘ญ๐’) = ๐Ÿ for ๐Ÿ โ‰ค ๐’ โ‰ค ๐Ÿ“ and for โ‰ฅ ๐Ÿ” ๐‘บ๐’…๐’Š๐’Ž (๐‘ญ๐’) = โŒˆ๐Ÿ๐’+๐Ÿ‘

๐Ÿ“ โŒ‰. We also give some an issue regarding the topic of star metric dimension for another researcher as follows.

If given a connected graph ๐‘ฎ with the order equals ๐’ vertex, determine star metric dimension of some product of graphs.

ACKNOWLEDGEMENTS

The authors would like to thank you very much for the support from LPPM Universitas Muhammadiyah Jember.

AUTHORโ€™S CONTRIBUTIONS

The authors discussed the results and contributed to from the start to final manuscript.

CONFLICT OF INTEREST

There are no conflicts of interest declared by the authors.

REFERENCES

Kang, C. X., Yero, I. G., & Yi, E. (2018). The fractional strong metric dimension in three graph products. Discrete Applied Mathematics, 251, 190โ€“203. https://doi.org/10.1016/j.dam.2018.05.051

Kuziak, D., Puertas, M. L., Rodrรญguez-Velรกzquez, J. A., & Yero, I. G. (2018). Strong resolving graphs: The realization and the characterization problems. Discrete Applied Mathematics, 236, 270โ€“287.

https://doi.org/10.1016/j.dam.2017.11.013

Kuziak, D., Rodriguez-Velazquez, J. A., & Yero, I. G. (2017). Computing the metric dimension of a graph from primary subgraphs. Discussiones Mathematicae - Graph Theory, 37(1), 273โ€“293. https://doi.org/10.7151/dmgt.1934

Kuziak, D., Yero, I. G., & Rodrรญguez-Velรกzquez, J. A. (2013). On the strong metric dimension of corona product graphs and join graphs. Discrete Applied Mathematics, 161(7โ€“8), 1022โ€“1027. https://doi.org/10.1016/j.dam.2012.10.009

Mutia, N. (2015). Dimensi Metrik Bintang dari Graf Serupa Roda. 001.

Mutianingsih, N., Asrining, U., & Uzlifah. (2016). Membandingkan Dimensi Metrik dan Dimensi Metrik Bintang. Prosiding Seminar Nasional Matematika 2016, Universita.

Saifudin, I., Umilasari, R., Program, E. S., & Jember, U. M. (2021). Automatic Aircraft Navigation Using Star Metric Dimension Theory in Fire Protected Forest Areas. 5(2), 294โ€“304.

Saputro, S. W., Mardiana, N., & Purwasih, I. A. (2017). The metric dimension of comb product graphs. Matematicki Vesnik, 69(4), 248โ€“258.

Yero, I. G., Kuziak, D., & Rodrรญguez-Velรกzquez, J. A. (2011). On the metric dimension of corona product graphs. Computers and Mathematics with Applications, 61(9), 2793โ€“2798. https://doi.org/10.1016/j.camwa.2011.03.046

Referensi

Dokumen terkait