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 = {๐ง1, ๐ง2, โฆ , ๐ง๐} โ ๐(๐บ) called star resolving set of connected graph ๐บ 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(๐ข, ๐ง), it is the shortest path from vertex ๐ข to ๐ง for every ๐ข, ๐ง โ ๐(๐บ). 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 = {๐ง1, ๐ง2, โฆ , ๐ง๐} โ ๐(๐บ) called star resolving set of connected graph ๐บ 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(๐ข, ๐ง), it is the shortest path from vertex ๐ข to ๐ง for every ๐ข, ๐ง โ ๐(๐บ). 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 ๐บ which denoted by ๐๐๐๐(๐บ). 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 ๐๐๐๐(๐พ๐) = ๐ โ 1, for ๐ โฅ 3, bipartite graph ๐พ2,๐ has ๐๐๐๐ (๐พ2,๐) = ๐, for ๐ โฅ 3. Besides complete bipartite graph hasnโt star metric dimension or for ๐, ๐ โฅ 3 or it can said that ๐๐๐๐ (๐พ๐,๐) = 0. Another graph, that is Fan graph has ๐๐๐๐ (๐น๐) = 2 for 2 โค ๐ โค 5 and for ๐ โฅ 6 ๐๐๐๐ (๐น๐) = โ2๐+3
5 โ.
Keywords: Metric Dimension; Star Basis; Star Metric Dimension; Star Resolving Set; Complete Bipartite
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star basis and its cardinality is called star metric dimension of ๐บ is ๐๐๐๐(๐บ) (Mutia, 2015).
Figure 1. Star Graph (๐บ๐) with ๐ ๐๐(๐บ๐) = ๐
Figure 2 shows a wheel graph (๐6) with the vertex set is ๐(๐6) = {๐, ๐, ๐, ๐, ๐, ๐, ๐}, let the star resolving set is ๐ = {๐, ๐, ๐}.
The representation every vertex of ๐(๐6) to ๐ are:
๐(๐|๐) = {0,1,1}
๐(๐|๐) = {1,1,1}
๐(๐|๐) = {1,1,0}
๐(๐|๐) = {1,2,1}
๐(๐|๐) = {1,2,2}
๐(๐|๐) = {1,1,2}
๐(๐|๐) = {1,0,2}
We can see that every vertex of ๐(๐6) has different representation to ๐, then Z is star resolving set of ๐6. Besides the Figure 3 show that if we take |๐| = 2, and suppose ๐ = {๐, ๐}. Then, there are some vertices have same representation to ๐, for example ๐(๐|๐) = {1,1} = ๐(๐|๐) = {1,1}. Thus ๐ = {๐, ๐} is not star resolving set of ๐6. 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 (๐พ๐) with star resolving set equals three
Figure 3. Wheel graph (๐พ๐)
Theorem 1. If ๐๐ is wheel graph with the order ๐ + 1 and ๐ โฅ 7, then star metric dimension ๐ ๐๐๐(๐๐) = โ๐
2โ. (Mutia, 2015) Theorem 2. If ๐บ2๐is gir graph with the order order 2๐ + 1 and ๐ โฅ 5, then star metric dimension ๐ ๐๐๐(๐บ2๐) = 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.
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 (๐๐๐๐) 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(๐ข, ๐ง), it is the shortest path from vertex ๐ข to ๐ง for every ๐ข, ๐ง โ ๐(๐บ).
c) Verifying representation of each vertex ๐ข element ๐บ to local resolving set ๐ starting for the smallest cardinality.
d) If the representation of each adjacent vertex to ๐ is different, then ๐๐๐๐(๐บ) = |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 ๐บ be a connected graph, ๐ โ ๐(๐บ), ๐ consist of star resolving set of graph ๐บ and ๐ form a star graph, then ๐ is star metric dimension of ๐บ.
Proof. Let ๐ = {๐ข๐|๐ = 1,2, โฆ , ๐} โ ๐(๐บ) is star resolving set of graph ๐บ and ๐ โ ๐(๐บ). Let ๐ โ ๐, because ๐ star resolving set, for every ๐ข, ๐ฃ โ ๐(๐บ) then ๐(๐ข|๐) โ ๐(๐ฃ|๐) and ๐(๐ข|๐) โ ๐(๐ฃ|๐) because ๐ โ ๐. Next, because ๐ form star graph, then ๐ is star resolving set of graph ๐บ.โ
Lemma 4. If ๐บ be a connected graph, ๐ โ ๐(๐บ) and For every ๐ฃ๐, ๐ฃ๐โ ๐ then ๐(๐ฃ๐|๐) โ ๐(๐ฃ๐|๐).
Proof. Let ๐ = {๐ฃ1, ๐ฃ2, ๐ฃ3, โฆ , ๐ฃ๐} โ ๐(๐บ). Because for every ๐ฃ๐, ๐ฃ๐โ ๐ with ๐ โ ๐ then ๐(๐ฃ๐, ๐ฃ๐) = 0 and ๐(๐ฃ๐, ๐ฃ๐) โ 0, then there exist 0 of ith element in ๐(๐ฃ๐|๐) for every ๐ฃ๐โ ๐. As a result ๐(๐ฃ๐|๐๐) โ ๐(๐ฃ๐|๐๐) for ๐ โ ๐. โ
Theorem 5. If ๐ โฅ 3, then ๐๐๐๐(๐พ๐) = ๐ โ 1.
Proof. Let ๐(๐พ๐) = {๐ฃ๐|๐ = 1,2,3, โฆ , ๐ }and๐ธ(๐พ๐) = {๐ฃ๐๐ฃ๐|๐, ๐ = 1,2,3, โฆ , ๐, ๐ โ ๐}with ๐ โฅ 3. Choose ๐ = {๐ฃ๐|๐ = 1,2,3, โฆ , ๐ โ 1} then |๐| = ๐ โ 1. See at Lemma 4, we get ๐(๐ฃ๐|๐) โ ๐(๐ฃ๐|๐) for every ๐ฃ๐, ๐ฃ๐โ ๐ with ๐ โ ๐. Then, because ๐(๐ฃ๐|๐) =
(1,1,1,1, โฆ ,1โ
(๐โ1)โ๐ก๐ข๐๐๐
), so ๐ is resolving set of graph ๐พ๐. In other side, because for every ๐ฃ๐โ ๐ with ๐ = 2,3,4, โฆ , ๐ โ 1 then ๐ฃ1๐ฃ๐โ
๐ธ(๐พ๐), thus ๐ form star graph ๐พ1,๐โ2 then ๐ is star resolving set of graph ๐พ๐. Next, because ๐๐๐ (๐พ๐) = ๐ โ 1, it clearly that ๐ is star metric dimension with minimum cardinality then it can conclude that ๐๐๐๐(๐พ๐) = ๐ โ 1. โ
Theorem 6. If ๐ โฅ 2, then ๐๐๐๐ (๐พ2,๐) = ๐.
Proof. Let ๐ (๐พ2,๐) = {๐1, ๐2, ๐๐|๐ = 1,2, โฆ , ๐} and ๐ธ (๐พ2,๐) = {๐1๐๐, ๐2๐๐ |๐ = 1,2,3, โฆ , ๐}. Choose ๐ = {๐1, ๐๐|๐ = 1,2,3, โฆ , ๐ โ 1}
then |๐| = ๐. See at Lemma 4, we have ๐ (๐1|๐) โ ๐(๐๐|๐) and ๐(๐๐|๐) โ ๐(๐๐|๐) for every ๐1, ๐๐, ๐๐, ๐๐ โ ๐ with ๐ โ ๐.
Then, because ๐ (๐2|๐) = (2, 1,1,1, โฆ ,1โ
(๐โ1)โ๐ก๐ข๐๐๐
) and ๐(๐๐|๐) = (1, 2,2,2, โฆ ,2โ
(๐โ1)โ๐ก๐ข๐๐๐
), thus ๐ is resolving set of ๐พ2,๐. In other side, because
for every ๐๐โ ๐ with ๐ = 1,2,3, โฆ , ๐ โ 1 then ๐1๐๐โ ๐ธ(๐พ2,๐), hence ๐ form star graph ๐พ1,๐โ1 then ๐ is star resolving set of ๐พ2,๐. Next, because ๐๐๐ (๐พ2,๐) = ๐, it clearly that ๐ is star resolving set with minimum cardinality. Therefore we can
conclude that ๐๐๐๐ (๐พ2,๐) = ๐. โ
Theorem 7. If ๐, ๐ โฅ 3, then ๐๐๐๐ (๐พ๐,๐) = 0.
Proof. Let ๐(๐พ๐,๐) = {๐๐|๐ = 1,2,3, โฆ , ๐} โช { ๐๐|๐ = 1,2, โฆ , ๐}and๐ธ(๐พ๐,๐) = {๐๐๐๐|๐ = 1,2,3, โฆ , ๐ ; ๐ = 1,2,3, โฆ , ๐}with ๐, ๐ โฅ 3.
Since ๐พ๐,๐ is a complete bipartite graph, then there exist two possibilities for ๐:
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1. Select ๐ = {๐๐|๐ = 2,3,4, โฆ , ๐} โช {๐๐|๐ = 2,3,4, โฆ , ๐}, so that |๐| = ๐ + ๐ โ 2. Based on Lemma 4, we get that ๐(๐ข|๐) โ
๐(๐ฃ|๐) for every ๐ข, ๐ฃ โ ๐ with ๐ข โ ๐ฃ . Furthermore, Since ๐ (๐1|๐) = ( 2,2,2, โฆ ,2โ
(๐โ1)โ๐ก๐ข๐๐๐
, 1,1,1, โฆ ,1โ
(๐โ1)โ๐ก๐ข๐๐๐
) and ๐ (๐1|๐) =
( 1,1,1, โฆ ,1โ
(๐โ1)โ๐ก๐ข๐๐๐
, 2,2,2, โฆ ,2โ
(๐โ1)โ๐ก๐ข๐๐๐
), then ๐ is resolving set of ๐พ๐,๐. Furthermore, Since ๐ doesnโt form a star, then ๐ is not a
star resolving set of ๐พ๐,๐.
2. Select ๐ = {๐1, ๐1} so that |๐| = 2. Since ๐๐๐ (๐พ๐,๐) = ๐ + ๐ โ 2, it clearly shows that ๐ is not a resolving set of ๐พ๐,๐ so that ๐ is not a star resolving set of ๐พ๐,๐.
Furthermore, Since ๐๐๐ (๐พ๐,๐) = ๐ + ๐ โ 2, then ๐๐๐๐ (๐พ๐,๐) โฅ ๐ + ๐ โ 2. On the other hand, Since star subgraph of ๐พ๐,๐ only can be obtained by ๐ + 1 or ๐ + 1 vertices, then ๐๐๐๐ (๐พ๐,๐) โค ๐ + 1 or ๐๐๐๐ (๐พ๐,๐) โค ๐ + 1. Contradiction with the fact that ๐๐๐๐ (๐พ๐,๐) โฅ ๐ + ๐ โ 2. Consequently, there is no vertex set as star resolving set of ๐พ๐,๐ so that ๐๐๐๐ (๐พ๐,๐) = 0. โ
Theorem 8. If 2 โค ๐ โค 5, then ๐๐๐๐ (๐น๐) = 2.
Proof. Let ๐(๐น๐) = {๐ฃ, ๐ฃ๐|๐ = 1,2, โฆ , ๐} and ๐ธ(๐น๐) = {๐ฃ๐ฃ๐|๐ = 1,2, โฆ , ๐} โช {๐ฃ๐๐ฃ๐+1|๐ = 1,2, โฆ , ๐ โ 1}. There are for cases for ๐:
1. For ๐ = 2, select ๐ = {๐ฃ, ๐ฃ1} so that |๐| = 2. Since ๐(๐ฃ|๐) = (0,1), ๐ (๐ฃ1|๐) = (1,0) and ๐ (๐ฃ2|๐) = (1,1), then ๐ is a resolving set of ๐น2. While, since ๐ forms ๐พ1,1 star, then ๐ is a star resolving set of ๐น2. Next, take any singleton. Let
๐ = {๐ฃ}, then we get ๐ (๐ฃ1|๐) = ๐ (๐ฃ2|๐) = (1,1) so that ๐ is not a resolving set of ๐น2. Consequently, ๐ is not a resolving
set of ๐น2. So that, ๐ is star resolving set with minimum cardinality and ๐๐๐๐ (๐น2) = 2.
2. For ๐ = 3, select ๐ = {๐ฃ1, ๐ฃ2} so that |๐| = 2. Since ๐(๐ฃ|๐) = (1,1) , ๐ (๐ฃ1|๐) = (0,1) , ๐ (๐ฃ2|๐) = (1,0) and ๐ (๐ฃ3|๐) = (2,1), then ๐ is a resolving set of ๐น3. While, since ๐ forms a ๐พ1,1, then ๐ is star resolving set of ๐น3. Next, take any singleton. There are two possibilities: (i) ๐ฃ with deg(๐ฃ) = 2; or (ii) ๐ฃ with deg(๐ฃ) = 3.
(i) Let ๐ = {๐ฃ1}, then we get ๐(๐ฃ|๐) = ๐ (๐ฃ2|๐) = (1) so that ๐ is not a resolving set of ๐น3. Consequently, ๐ is not a resolving set of ๐น3.
(ii) Let ๐ = {๐ฃ}, then we get ๐ (๐ฃ1|๐) = ๐ (๐ฃ2|๐) = ๐ (๐ฃ3|๐) = (1) so that ๐ is not a resolving set of ๐น3. Consequently, ๐ is not a resolving set of ๐น3.
So that, ๐ is star resolving set with minimum cardinality and ๐๐๐๐ (๐น3) = 2.
3. For ๐ = 4, select ๐ = {๐ฃ2, ๐ฃ3} so that |๐| = 2. Since ๐(๐ฃ|๐) = (1,1), ๐ (๐ฃ1|๐) = (1,2), ๐ (๐ฃ2|๐) = (0,1), ๐ (๐ฃ3|๐) = (1,0)
and ๐ (๐ฃ4|๐) = (2,1), then ๐ is a resolving set of ๐น4. While, since ๐ forms a ๐พ1,1, then ๐ is star resolving set of ๐น4. Next, take any singleton. There are two possibilities: (i) ๐ฃ with deg(๐ฃ) = 2; or (ii) ๐ฃ with deg(๐ฃ) = 3.
(i) Let ๐ = {๐ฃ1}, then we get ๐(๐ฃ|๐) = ๐ (๐ฃ2|๐) = (1) so that ๐ is not a resolving set of ๐น4. Consequently, ๐ is not a resolving set of ๐น4.
(ii) Let ๐ = {๐ฃ} , then we get ๐ (๐ฃ1|๐) = ๐ (๐ฃ2|๐) = ๐ (๐ฃ3|๐) = ๐ (๐ฃ4|๐) = (1) so that ๐ is not a resolving set of ๐น4. Consequently, ๐ is not a resolving set of ๐น3.
So that, ๐ is a star resolving set with minimum cardinality and ๐๐๐๐ (๐น4) = 2.
4. For ๐ = 5, select ๐ = {๐ฃ2, ๐ฃ3} so that |๐| = 2. Since ๐(๐ฃ|๐) = (1,1), ๐ (๐ฃ1|๐) = (1,2), ๐ (๐ฃ2|๐) = (0,1), ๐ (๐ฃ3|๐) = (1,0),
๐ (๐ฃ4|๐) = (2,1) and ๐ (๐ฃ5|๐) = (2,2), then ๐ is a resolving set of ๐น5. On the other hand, Since ๐ forms a ๐พ1,1, then ๐ is a star resolving set of ๐น5. Furthermore, take any singleton. There are two possibilities: (i) ๐ฃ with deg(๐ฃ) = 2; or (ii) ๐ฃ with deg(๐ฃ) = 3.
(i) Let ๐ = {๐ฃ1}, then we get ๐(๐ฃ|๐) = ๐ (๐ฃ2|๐) = (1) so that ๐ is not a resolving set of ๐น5. Consequently, ๐ is not a resolving set of ๐น5.
(ii) Let ๐ = {๐ฃ}, then we get ๐ (๐ฃ1|๐) = ๐ (๐ฃ2|๐) = ๐ (๐ฃ3|๐) = ๐ (๐ฃ4|๐) = ๐ (๐ฃ5|๐) = (1) so that ๐ is not a resolving set of ๐น5. Consequently, ๐ is not a resolving set of ๐น5.
So that, ๐ is a star resolving set with minimum cardinality and ๐๐๐๐ (๐น5) = 2.
From the four possibilities above, we get that for ๐ = 2,3,4,5, ๐๐๐๐(๐น๐) = 2. โ Theorem 9. If ๐ โฅ 6, then ๐๐๐๐ (๐น๐) = โ2๐+3
5 โ.
Proof. Let ๐(๐น๐) = {๐ฃ, ๐ฃ๐|๐ = 1,2, โฆ , ๐} and ๐ธ(๐น๐) = {๐ฃ๐ฃ๐|๐ = 1,2, โฆ , ๐} โช {๐ฃ๐๐ฃ๐+1|๐ = 1,2, โฆ , ๐ โ 1}. There are three cases for ๐:
1. For ๐ โก 1 (๐๐๐ 5) or ๐ โก 3 (๐๐๐ 5) , select ๐ = {๐ฃ, ๐ฃ2, ๐ฃ4, ๐ฃ7, ๐ฃ9, โฆ , ๐ฃ5๐โ3, ๐ฃ5๐โ1, โฆ , ๐ฃ๐โ2} so that |๐| = โ2๐+3
5 โ . Based on Lemma 4, we get that ๐(๐ข|๐) โ ๐(๐ฃ|๐) for every ๐ข, ๐ฃ โ ๐ with ๐ข โ ๐ฃ. Furthermore, Since for every ๐ฃ๐โ ๐(๐น๐) we get:
๐(๐ฃ๐|๐) =
{
(
1,2,2,2, โฆ ,2, 1โ
(๐ 3+1)๐กโ
, 2,2,2, โฆ ,2 )
, ๐ โก 0 (๐๐๐ 5)
(
1,2,2,2, โฆ ,2, 1โ
(โ๐ 2โโโ๐
10โ+1)๐กโ
, 2,2,2, โฆ ,2 )
, ๐ โก 1 (๐๐๐ 5)
(
1,2,2,2, โฆ ,2, 1โ
(โ๐ 3โ+โ๐
15โ+1) ๐กโ
, 1โ
(โ๐ 3โ+โ๐
15โ+2) ๐กโ
, 2,2,2, โฆ ,2 )
, ๐ โก 3 (๐๐๐ 5)
So that, ๐ is a resolving set of ๐น๐. Furthermore, Since for every ๐ฃ5๐โ3, ๐ฃ5๐โ1โ ๐ we get ๐ฃ๐ฃ5๐โ3โ ๐ธ(๐น๐) and ๐ฃ๐ฃ5๐โ1โ ๐ธ(๐น๐), then ๐ forms a ๐พ
1,โ2๐+3
5 โโ1 so that ๐ is a star resolving set of ๐น๐. Furthermore, take any ๐ โ ๐(๐น๐) with |๐| < |๐|,
|๐| = |๐| โ 1. Then there are two cases for ๐:
(i) ๐ doesnโt consist ๐ฃ. Let ๐ = {๐ฃ2, ๐ฃ4, ๐ฃ7, ๐ฃ9, โฆ , ๐ฃ5๐โ3, ๐ฃ5๐โ1, โฆ , ๐ฃ๐โ2}. Then ๐ doesnโt form a star.
(ii) ๐ consists ๐ฃ. Let ๐ = {๐ฃ, ๐ฃ2, ๐ฃ4, ๐ฃ7, ๐ฃ9, โฆ , ๐ฃ5๐โ3, ๐ฃ5๐โ1, โฆ , ๐ฃ๐โ7}. There exist ๐ฃ๐โ2, ๐ฃ๐โ1, ๐ฃ๐โ ๐(๐น๐) โ ๐, so that ๐(๐ฃ๐โ2|๐) = ๐(๐ฃ๐โ1|๐) = ๐(๐ฃ๐|๐) = (2,2,2, โฆ ,2). Consequently, ๐ is not a resolving set of ๐น๐.
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 ๐๐๐๐ (๐น๐) = โ2๐+3
5 โ For ๐ โก 1 (๐๐๐ 5) or ๐ โก 3 (๐๐๐ 5).
204
2. For ๐ โก 2 (๐๐๐ 5) or ๐ โก 4 (๐๐๐ 5) , select ๐ = {๐ฃ, ๐ฃ2, ๐ฃ4, ๐ฃ7, ๐ฃ9, โฆ , ๐ฃ5๐โ3, ๐ฃ5๐โ1, โฆ , ๐ฃ๐} so that |๐| = โ2๐+3
5 โ . Based on Lemma 4, we get that ๐(๐ข|๐) โ ๐(๐ฃ|๐) for every ๐ข, ๐ฃ โ ๐ with ๐ข โ ๐ฃ. Furthermore, Since for every ๐ฃ๐โ ๐(๐น๐) we get:
๐(๐ฃ๐|๐) =
{
(
1,2,2,2, โฆ ,2, 1โ
(๐ 3+1)
๐กโ
, 2,2,2, โฆ ,2 )
, ๐ โก 0 (๐๐๐ 5)
(
1,2,2,2, โฆ ,2, 1โ
(โ๐ 2โโโ๐
10โ+1) ๐กโ
, 2,2,2, โฆ ,2 )
, ๐ โก 1 (๐๐๐ 5)
(
1,2,2,2, โฆ ,2, 1โ
(โ๐ 3โ+โ๐
15โ+1)๐กโ
, 1โ
(โ๐ 3โ+โ๐
15โ+2)๐กโ
, 2,2,2, โฆ ,2 )
, ๐ โก 3 (๐๐๐ 5)
So that, ๐ is a resolving set of ๐น๐. Furthermore, Since for every ๐ฃ5๐โ3, ๐ฃ5๐โ1โ ๐ we get ๐ฃ๐ฃ5๐โ3โ ๐ธ(๐น๐) and ๐ฃ๐ฃ5๐โ1โ ๐ธ(๐น๐), then ๐ forms a ๐พ
1,โ2๐+3
5 โโ1 so that ๐ is a star resolving set of ๐น๐. Furthermore, take any ๐ โ ๐(๐น๐) with |๐| < |๐|,
|๐| = |๐| โ 1. Then there are two cases for ๐:
(i) ๐ doesnโt consist ๐ฃ. Let ๐ = {๐ฃ2, ๐ฃ4, ๐ฃ7, ๐ฃ9, โฆ , ๐ฃ5๐โ3, ๐ฃ5๐โ1, โฆ , ๐ฃ๐}. Then ๐ doesnโt form a star.
(ii) ๐ consists ๐ฃ . Let ๐ = {๐ฃ, ๐ฃ2, ๐ฃ4, ๐ฃ7, ๐ฃ9, โฆ , ๐ฃ5๐โ3, ๐ฃ5๐โ1, โฆ , ๐ฃ๐โ5}. There exists ๐ฃ๐โ2, ๐ฃ๐โ1, ๐ฃ๐โ ๐(๐น๐) โ ๐ , so that ๐(๐ฃ๐โ2|๐) = ๐(๐ฃ๐โ1|๐) = ๐(๐ฃ๐|๐) = (2,2,2, โฆ ,2). Consequently, ๐ is not a resolving set of ๐น๐.
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 ๐๐๐๐ (๐น๐) = โ2๐+3
5 โ For ๐ โก 2 (๐๐๐ 5) or ๐ โก 4 (๐๐๐ 5).
3. For ๐ โก 0 (๐๐๐ 5), select ๐ = {๐ฃ, ๐ฃ2, ๐ฃ4, ๐ฃ7, ๐ฃ9, โฆ , ๐ฃ5๐โ3, ๐ฃ5๐โ1, โฆ , ๐ฃ๐โ1} so that |๐| = โ2๐+3
5 โ. Based on Lemma 4, we get that ๐(๐ข|๐) โ ๐(๐ฃ|๐) for every ๐ข, ๐ฃ โ ๐ with ๐ข โ ๐ฃ. Furthermore, Since for every ๐ฃ๐โ ๐(๐น๐) we get:
๐(๐ฃ๐|๐) =
{
(
1,2,2,2, โฆ ,2, 1โ
(๐ 3+1)
๐กโ
, 2,2,2, โฆ ,2 )
, ๐ โก 0 (๐๐๐ 5)
(
1,2,2,2, โฆ ,2, 1โ
(โ๐ 2โโโ๐
10โ+1) ๐กโ
, 2,2,2, โฆ ,2 )
, ๐ โก 1 (๐๐๐ 5)
(
1,2,2,2, โฆ ,2, 1โ
(โ๐ 3โ+โ๐
15โ+1)๐กโ
, 1โ
(โ๐ 3โ+โ๐
15โ+2)๐กโ
, 2,2,2, โฆ ,2 )
, ๐ โก 3 (๐๐๐ 5)
So that, ๐ is a resolving set of ๐น๐. Furthermore, Since for every ๐ฃ5๐โ3, ๐ฃ5๐โ1โ ๐ we get ๐ฃ๐ฃ5๐โ3โ ๐ธ(๐น๐) and ๐ฃ๐ฃ5๐โ1โ ๐ธ(๐น๐), then ๐ forms a ๐พ
1,โ2๐+3
5 โโ1 so that ๐ is a star resolving set of ๐น๐. Furthermore, take any ๐ โ ๐(๐น๐) with |๐| < |๐|,
|๐| = |๐| โ 1. Then there are two cases for ๐:
(iii) ๐ doesnโt consist ๐ฃ. Let ๐ = {๐ฃ2, ๐ฃ4, ๐ฃ7, ๐ฃ9, โฆ , ๐ฃ5๐โ3, ๐ฃ5๐โ1, โฆ , ๐ฃ๐โ1}. Then ๐ doesnโt form a star.
(iv) ๐ consist ๐ฃ . Let ๐ = {๐ฃ, ๐ฃ2, ๐ฃ4, ๐ฃ7, ๐ฃ9, โฆ , ๐ฃ5๐โ3, ๐ฃ5๐โ1, โฆ , ๐ฃ๐โ6}. There exists ๐ฃ๐โ2, ๐ฃ๐โ1, ๐ฃ๐โ ๐(๐น๐) โ ๐ , so that ๐(๐ฃ๐โ2|๐) = ๐(๐ฃ๐โ1|๐) = ๐(๐ฃ๐|๐) = (2,2,2, โฆ ,2). Consequently, ๐ is not a resolving set of ๐น๐.
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 ๐๐๐๐ (๐น๐) = โ2๐+3
5 โ For ๐ โก 0 (๐๐๐ 5) or ๐ โก 3 (๐๐๐ 5).
Based on three cases above, we get that for ๐ โฅ 6 we get ๐๐๐๐(๐น๐) = โ2๐+3
5 โ. โ
4. CONCLUSION
Based on the all the explanations above, we can conclude that complete graph has ๐บ๐ ๐๐(๐ฒ๐) = ๐ โ ๐, for ๐ โฅ ๐, bipartite graph ๐ฒ๐,๐ has ๐บ๐ ๐๐ (๐ฒ๐,๐) = ๐, for ๐ โฅ ๐. Besides complete bipartite graph hasnโt star metric dimension or for ๐, ๐ โฅ ๐ or it can said that ๐บ๐ ๐๐ (๐ฒ๐,๐) = ๐. Another graph, that is Fan graph has ๐บ๐ ๐๐ (๐ญ๐) = ๐ for ๐ โค ๐ โค ๐ and for โฅ ๐ ๐บ๐ ๐๐ (๐ญ๐) = โ๐๐+๐
๐ โ. We also give some an issue regarding the topic of star metric dimension for another researcher as follows.
If given a connected graph ๐ฎ 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.
AUTHORโS 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.
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