On the study of Rainbow Antimagic Coloring of Special Graphs CAUCHY –Jurnal Matematika Murni dan Aplikasi Volume 7(4) (2023), Pages 585-596 p-ISSN: 2086-0382; e-ISSN: 2477-3344 Submitted: October 19, 2022 Reviewed: February 20, 2023 Accepted: March 20, 2023 DOI: http://dx.doi.org/10.18860/ca.v7i4.17836 On the study of Rainbow Antimagic Coloring of Special Graphs Dafik1,2,*, Riniatul Nur Wahidah 1,2, Ermita Rizki Albirri 1,2 , Sharifah Kartini Said Husain 3 1Mathematics Edu. Depart. University of Jember, Indonesia 2PUI-PT Combinatorics and Graph, CGANT, University of Jember, Indonesia 3Institute for Mathematical Research, University Putra Malaysia, Malaysia Email: d.dafik@unej.ac.id ABSTRACT Let 𝐺 be a connected graph with vertex set 𝑉(𝐺) and edge set 𝐸(𝐺). The bijective function 𝑓:𝑉(𝐺) β†’ {1,2,…,|𝑉(𝐺)|} is said to be a labeling of graph where 𝑀(π‘₯𝑦) = 𝑓(π‘₯) + 𝑓(𝑦) is the associated weight for edge π‘₯𝑦 ∈ 𝐸(𝐺). If every edge has different weight, the function 𝑓 is called an edge antimagic vertex labeling. A path 𝑃 in the vertex-labeled graph 𝐺, with every two edges π‘₯𝑦,π‘₯′𝑦′ ∈ 𝐸(𝑃) satisfies 𝑀(π‘₯𝑦) β‰  𝑀(π‘₯′𝑦′) is said to be a rainbow path. The function 𝑓 is called a rainbow antimagic labeling of 𝐺, if for every two vertices π‘₯,𝑦 ∈ 𝑉(𝐺), there exists a rainbow π‘₯ βˆ’ 𝑦 path. Graph 𝐺 admits the rainbow antimagic coloring, if we assign each edge π‘₯𝑦 with the color of the edge weight 𝑀(π‘₯𝑦). The smallest number of colors induced from all edge weights of edge antimagic vertex labeling is called a rainbow antimagic connection number of 𝐺, denoted by π‘Ÿπ‘Žπ‘(𝐺). In this paper, we study rainbow antimagic connection numbers of octopus graph 𝑂𝑛, sandat graph 𝑆𝑑𝑛, sun flower graph 𝑆𝑓𝑛, volcano graph 𝑉𝑛 and semi jahangir graph 𝐽𝑛. Copyright Β© 2023 by Authors, Published by CAUCHY Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0/) Keywords: antimagic labeling; rainbow coloring; rainbow antimagic connection number; special graphs INTRODUCTION The definition of graph used in this paper follows from Chartrand and Zhang [9]. In the latest days, graph theory has many applications, one of them is graph coloring. The application of graph coloring can be found in many area, such as data mining, image segmentation, clustering, image capturing, networking. Chartrand, et al. [10] extended the graph coloring concept into a rainbow coloring of graph. Let 𝑐:𝐸(𝐺) β†’ {1,2, . . . ,π‘˜},π‘˜ ∈ β„• be the edge coloring of a connected graph where the two adjacent edges may have the same color. If for every two vertices π‘₯,𝑦 ∈ 𝑉(𝐺), there exists a rainbow π‘₯ βˆ’ 𝑦 path, if no two edges of the π‘₯ βˆ’ 𝑦 path are the same color, then the path is called a rainbow path. A coloring of graph 𝐺 is said to be rainbow connection, if for every two vertices π‘₯,𝑦 ∈ 𝑉(𝐺) have a rainbow π‘₯ βˆ’ 𝑦 path. The edge colored 𝐺 which every two different vertices have a rainbow connection is called rainbow coloring of graph, see [10]. Some results in regards to the concept of rainbow coloring of graphs can been found by Nabila, et al [21] and Ma, et al. [19]. Some other type of rainbow coloring are rainbow vertex coloring and rainbow total coloring. Some relevant results of rainbow vertex coloring can be found in Lie. H, et al. [15], http://dx.doi.org/10.18860/ca.v7i4.17836 https://creativecommons.org/licenses/by-sa/4.0/ On the study of Rainbow Antimagic Coloring of Special Graphs Dafik 586 Bustan et al. [8] and Li. X et al. [17], while some results of total rainbow coloring can be found results in Lie. H et al. [16] and Ma. Y et al.[20]. Furthermore, the other concepts in graph theory is graph labeling, one of the concept of graph labeling is an antimagic labeling of graph 𝐺, defined by Hartsfield and Ringel [13]. Baca et al. has found some antimagic labeling results in [4], [5], [6]. Moreover, some results on antimagic labeling have been contributed by Dafik 𝑒𝑑 π‘Žπ‘™. in [11]. In addition, the research on antimagic labeling can also be found in several papers [2], [22], [25]. Arumugam et al. [3], defined a new concept by combining graph coloring and graph labeling. The bijective function 𝑓 ∢ 𝐸(𝐺) β†’ {1,2, . . . , |𝐸(𝐺)|}, the vertex weight of the vertex π‘₯ is 𝑀(π‘₯) = βˆ‘ 𝑓(π‘₯𝑦) π‘₯π‘¦βˆˆπΈ(π‘₯) and 𝐸(π‘₯) is the set of edges incident to π‘₯ for every π‘₯ ∈ 𝑉(𝐺). If for every two adjacent vertices π‘₯,𝑦 ∈ 𝑉 (𝐺),𝑀(π‘₯) β‰  𝑀(𝑦), then the bijective function 𝑓 is called a local antimagic labeling. So, each local antimagic label is a vertex coloring in 𝐺 with vertex π‘₯ colored with 𝑀(π‘₯). Based on the definition of Arumugam [3], Dafik 𝑒𝑑 π‘Žπ‘™. [12] defined the combination of the concepts of antimagic labeling and rainbow coloring into a new concept called rainbow antimagic coloring. In this study, we will study the combination of rainbow coloring and antimagic labeling, and it tends to the new notion, namely a rainbow antimagic coloring. The lower bound of the rainbow antimagic connection number has been determined in Septory et al. stated in the following lemma. Lemma 1. Let 𝐺 be any connected graph. Let π‘Ÿπ‘(𝐺) and Ξ”(𝐺) be the rainbow connection number of 𝐺 and the maximum degree of 𝐺, π‘Ÿπ‘Žπ‘(𝐺) β‰₯ π‘šπ‘Žπ‘₯ {π‘Ÿπ‘(𝐺),Ξ”(𝐺)}. While Dafik et al. also characterised the existence of rainbow 𝑒 βˆ’ 𝑣 path of any graph of π‘‘π‘–π‘Žπ‘š(𝐺) ≀ 2 in the following theorem. Theorem 1. Let 𝐺 be a connected graph of diameter π‘‘π‘–π‘Žπ‘š(𝐺) ≀ 2. Let 𝑓 be any bijective function from 𝑉(𝐺) to the set {1,2,…, |𝑉(𝐺)| }, there exists a rainbow π‘₯ βˆ’ 𝑦 path. Some other results in regards on this notion can be read on [1], [7], [12], [14], [23] and [24]. In this paper, we will study the rainbow antimagic connection number of octopus graph 𝑂𝑛, sandat graph 𝑆𝑑𝑛, sun flower graph 𝑆𝑓𝑛, volcano graph 𝑉𝑛 and semi jahangir graph 𝑆𝐽𝑛. METHOD To determine the number of rainbow antimagic coloring of graph, we use the following steps: 1. For any graph 𝐺, identify the set of vertices 𝑉(𝐺) and set of edges 𝐸(𝐺). 2. Analyze the lower bound of rainbow antimagic connection number (π‘Ÿπ‘Žπ‘) based on Lemma: π‘Ÿπ‘Žπ‘(𝐺) β‰₯ max {π‘Ÿπ‘(𝐺),Ξ”(𝐺)}. 3. Label the vertices of the graph 𝐺 with the function: 𝑉(𝐺) β†’ {1,2,3, . . . , |𝑉(𝐺)|}. 4. Determine the edge weight based on the sum of vertex label which incident with the edge. To calculate edge weight we give the function, 𝑀(𝑒𝑣) = 𝑓(𝑒) + 𝑓(𝑣) for 𝑒,𝑣 πœ– 𝑉(𝐺). 5. Verify that every two vertex in the graph 𝐺 have rainbow paths. If not, repeat the step 3. 6. Determine the upper bound of π‘Ÿπ‘Žπ‘(𝐺) from the number of different edge weight. 7. The exact value of rainbow antimagic connection number can be determined if lower On the study of Rainbow Antimagic Coloring of Special Graphs Dafik 587 bound is the same with upper bound of rainbow antimagic connection number. On the study of Rainbow Antimagic Coloring of Special Graphs Dafik 588 RESULTS AND DISCUSSION In this section, we will show our new results on those graph above stated in a theorem. We start to write the theorem, provide the cardinality of the graph, obtain lower and upper bound, establish the rainbow antimagic connection number and show the existence of rainbow path for any to vertices and finally conclude the proof. Theorem 2. For 𝑛 β‰₯ 3 , π‘Ÿπ‘Žπ‘(𝑂𝑛) = 2𝑛 . π‘ƒπ‘Ÿπ‘œπ‘œπ‘“. The octopus graph 𝑂𝑛 is a graph with vertex set 𝑉( 𝑂𝑛 ) = {π‘₯} βˆͺ { 𝑦𝑖, 𝑧𝑖,1 ≀ 𝑗 ≀ 𝑛}, and edge set 𝐸(𝑂𝑛) = {π‘₯𝑦𝑖,π‘₯𝑧𝑖,1 ≀ 𝑖 ≀ 𝑛} βˆͺ {𝑦𝑖𝑦𝑖+1, 1 ≀ 𝑖 ≀ 𝑛 βˆ’ 1}. The cardinality of vertex set is |𝑉(𝑂𝑛)| = 2𝑛 + 1 and the cardinality of edge set is |𝐸(𝑂𝑛)| = 3𝑛 βˆ’ 1. Based on definition of octopus graph, the graph 𝑂𝑛 has maximum degree of Ξ” (𝑂𝑛) = 2𝑛. To prove the rainbow antimagic connection number of 𝑂𝑛, the first step is to determine the lower bound of π‘Ÿπ‘Žπ‘(𝑂𝑛). Based on Lemma 1. we have π‘Ÿπ‘Žπ‘(𝑂𝑛) β‰₯ Ξ”(𝑂𝑛). Since, the labels of the vertices with the bijection 𝑓:𝑉(𝑂𝑛) β†’ {1,2,…,|𝑉(𝑂𝑛)|}, we have 𝑓(𝑒) β‰  𝑓(𝑣) for every vertex 𝑒,𝑣 ∈ 𝑉 (𝐺). It implies for each edge 𝑒π‘₯,𝑣π‘₯ ∈ 𝐸 (𝐺),𝑀 (𝑒π‘₯) β‰  𝑀 (𝑣π‘₯). Thus π‘Ÿπ‘Žπ‘ (𝑂𝑛) β‰₯ 2𝑛. The second step is to determine the upper bound of π‘Ÿπ‘Žπ‘(𝑂𝑛). Define the vertex labeling 𝑓 ∢ 𝑉(𝑂𝑛) β†’ {1,2, . . . ,2𝑛 + 1 } as follows. 𝑓(π‘₯) = 1 𝑓(𝑦𝑖) = { 3+𝑖 2 , for 𝑖 is odd 3+𝑛+𝑖 2 , for 𝑖 is even,𝑛 is odd 2+𝑛+𝑖 2 , for 𝑖 is even,𝑛 is even 𝑓(𝑧𝑖) = 𝑛 + 𝑖 + 1 , for 1 ≀ 𝑖 ≀ 𝑛 The edge weight 𝑓 can be expressed as 𝑀(π‘₯𝑧𝑖) = 2 + 𝑛 + 𝑖 , for 1 ≀ 𝑖 ≀ 𝑛 𝑀(π‘₯𝑦𝑖) = { 5+𝑖 2 , for 𝑖 is odd 5+𝑛+𝑖 2 , for 𝑖 is even,𝑛 is odd 4+𝑛+𝑖 2 , for 𝑖 is even,𝑛 is even 𝑀(𝑦𝑖𝑦𝑖+1) = { 7+2𝑖+𝑛 2 , for 1 ≀ 𝑖 ≀ 𝑛,𝑛 is odd 6+2𝑖+𝑛 2 , for 1 ≀ 𝑖 ≀ 𝑛,𝑛 is even The next step is to count the number of different edge weights inducing the rainbow antimagic coloring on the graph 𝑂𝑛. The edge weights are included in the sets 𝑀(π‘₯𝑦𝑖) = {3,4,5,…,𝑛 + 2} and 𝑀(π‘₯𝑧𝑖) = {𝑛 + 3,𝑛 + 4,𝑛 + 5,…,2𝑛 + 2}. The number of distinct colors of 𝑀(π‘₯𝑦𝑖) βˆͺ 𝑀(π‘₯𝑧𝑖) is 2𝑛. To prove this number, we use the formula of an arithmetic sequence formula. The following is an illustration of determining the number of distinct colors. π‘ˆπ‘  = π‘Ž + (𝑠 βˆ’ 1)𝑑 2𝑛 + 2 = 3 + (𝑠 βˆ’ 1)1 2𝑛 + 2 = 3 + 𝑠 βˆ’ 1 𝑠 = 2𝑛 On the study of Rainbow Antimagic Coloring of Special Graphs Dafik 589 It implies that the edge weight 𝑓 ∢ 𝑉(𝑂𝑛) β†’ {1,2, . . . ,2𝑛 + 1} induces a rainbow antimagic coloring of 2𝑛 colors. Therefore π‘Ÿπ‘Žπ‘ (𝑂𝑛 ) ≀ 2𝑛. Combining two bounds, we have the exact value of π‘Ÿπ‘Žπ‘ (𝑂𝑛) = 2𝑛. The last is to show the existence of the rainbow π‘₯ βˆ’ 𝑦 path of 𝑂𝑛. According to the Theorem 2, since π‘‘π‘–π‘Žπ‘š(𝑂𝑛) = 2, for every two vertices of the π‘₯,𝑦 ∈ 𝑉(𝐺) there is a rainbow π‘₯ βˆ’ 𝑦 path. It completes the proof. The illustration of a rainbow antimagic coloring of octopus graph 𝑂𝑛 can be seen in Figure 1. Figure 1. The illustration of rainbow antimagic coloring of octopus graph 𝑂7 Theorem 3. For 𝑛 β‰₯ 3, π‘Ÿπ‘Žπ‘(𝑆𝑑𝑛) = 3𝑛 . π‘ƒπ‘Ÿπ‘œπ‘œπ‘“. The sandat graph 𝑆𝑑𝑛 is a graph with vertex set 𝑉( 𝑆𝑑𝑛 ) = {π‘Ž} βˆͺ { π‘₯ 𝑖,𝑦𝑖,𝑧𝑖,1 ≀ 𝑖 ≀ 𝑛} and edge set 𝐸(𝑆𝑑𝑛) = {π‘Žπ‘₯𝑖,π‘Žπ‘¦π‘–,π‘Žπ‘§π‘–,π‘₯𝑖𝑦𝑖,𝑦𝑖𝑧𝑖 1 ≀ 𝑖 ≀ 𝑛}. The cardinality of vertex set is |𝑉(𝑆𝑑𝑛)| = 3𝑛 + 1 and the cardinality of edge set is |𝐸(𝑆𝑑𝑛)| = 5𝑛. Based on definition of sandat graph, the graph 𝑆𝑑𝑛 has maximum degree of Ξ” (𝑆𝑑𝑛) = 3𝑛. To prove the rainbow antimagic connection number of 𝑆𝑑𝑛 , the first step is to determine the lower bound of π‘Ÿπ‘Žπ‘(𝑆𝑑𝑛). Based on Lemma 1. we have π‘Ÿπ‘Žπ‘(𝑆𝑑𝑛) β‰₯ Ξ”(𝑆𝑑𝑛). Since, the labels of the vertices with the bijection 𝑓:𝑉(𝑆𝑑𝑛) β†’ {1,2,…,|𝑉(𝑆𝑑𝑛)|}, we have 𝑓(𝑒) β‰  𝑓(𝑣) for every vertex 𝑒,𝑣 ∈ 𝑉 (𝐺). It implies for each edge 𝑒π‘₯,𝑣π‘₯ ∈ 𝐸 (𝐺),𝑀 (𝑒π‘₯) β‰  𝑀 (𝑣π‘₯). Thus π‘Ÿπ‘Žπ‘ (𝑆𝑑𝑛) β‰₯ 3𝑛. The second step is to determine the upper bound of π‘Ÿπ‘Žπ‘(𝑆𝑑𝑛). Define the vertex labeling 𝑓 ∢ 𝑉(𝑆𝑑𝑛) β†’ {1,2, . . . ,3𝑛 + 1 } as follows. 𝑓(π‘Ž) = 2 𝑓(π‘₯𝑖) = 3𝑛 + 3 βˆ’ 2𝑖 , for 1 ≀ 𝑖 ≀ 𝑛 𝑓(𝑦𝑖) = { 1 , for 𝑖 = 𝑛 𝑖 + 1 , for ≀ 𝑖 ≀ 𝑛 𝑓(𝑧𝑖) = 3𝑛 + 2 βˆ’ 2𝑖 , for 1 ≀ 𝑖 ≀ 𝑛 The edge weight 𝑓 can be expressed as 𝑀(π‘Žπ‘₯𝑖) = 3𝑛 + 5 βˆ’ 2𝑖 , for 1 ≀ 𝑖 ≀ 𝑛 On the study of Rainbow Antimagic Coloring of Special Graphs Dafik 590 𝑀(π‘Žπ‘¦π‘–) = { 3 , for i = 1 𝑖 + 3 , for 2 ≀ 𝑖 ≀ 𝑛 𝑀(π‘Žπ‘§π‘–) = 3𝑛 + 4 βˆ’ 2𝑖 , for 1 ≀ 𝑖 ≀ 𝑛 𝑀(π‘₯𝑖𝑦𝑖) = { 3𝑛 + 2 , for 𝑖 = 1 3𝑛 + 4 βˆ’ 𝑖 , for 2 ≀ 𝑖 ≀ 𝑛 𝑀(𝑦𝑖𝑧𝑖) = { 3𝑛 + 1 , for 𝑖 = 1 3𝑛 + 3 βˆ’ 𝑖 , for 2 ≀ 𝑖 ≀ 𝑛 The next step is to count the number of different edge weights inducing the rainbow antimagic coloring on the graph 𝑆𝑑𝑛. The edge weights are included in the sets 𝑀(π‘Žπ‘₯𝑖) βˆͺ 𝑀(π‘Žπ‘¦π‘–) βˆͺ 𝑀(π‘Žπ‘§π‘–) βˆͺ 𝑀(π‘₯𝑖𝑦𝑖) βˆͺ 𝑀(𝑦𝑖𝑧𝑖) = {5,6,7,…,3𝑛 + 3 }. The number of distinct colors of 𝑀(π‘Žπ‘₯𝑖) βˆͺ 𝑀(π‘Žπ‘¦π‘–) βˆͺ 𝑀(π‘Žπ‘§π‘–) βˆͺ 𝑀(π‘₯𝑖𝑦𝑖) βˆͺ 𝑀(𝑦𝑖𝑧𝑖) is 3𝑛. Based on edge weights the number of edge wights is determined in the same way in Theorem 2. It implies that the edge weight 𝑓 ∢ 𝑉(𝑆𝑑𝑛) β†’ {1,2, . . . ,3𝑛 + 1} induces a rainbow antimagic coloring of 3𝑛 colors. Therefore π‘Ÿπ‘Žπ‘ (𝑆𝑑𝑛 ) ≀ 3𝑛. Combining two bounds, we have the exact value of π‘Ÿπ‘Žπ‘ (𝑆𝑑𝑛) = 3𝑛. The last is to show the existence of the rainbow π‘₯ βˆ’ 𝑦 path of 𝑆𝑑𝑛. According to the Theorem 1, since π‘‘π‘–π‘Žπ‘š(𝑆𝑑𝑛) = 2, for every two vertices of the π‘₯,𝑦 ∈ 𝑉(𝐺) there is a rainbow π‘₯ βˆ’ 𝑦 path. It completes the proof. The illustration of a rainbow antimagic coloring of sandat graph 𝑆𝑑𝑛 can be seen in Figure 2. Figure 2. The illustration of rainbow antimagic coloring of sandat graph 𝑆𝑑6. Theorem 4. For 𝑛 β‰₯ 4, π‘Ÿπ‘Žπ‘(𝑆𝑓𝑛) = 3𝑛 . π‘ƒπ‘Ÿπ‘œπ‘œπ‘“. The sunflower graph 𝑆𝑓𝑛 is a graph with vertex set 𝑉( 𝑆𝑓𝑛 ) = {𝑐} βˆͺ { π‘₯ 𝑖,𝑦𝑖,𝑧𝑖,1 ≀ 𝑖 ≀ 𝑛} and edge set 𝐸(𝑆𝑓𝑛) = {𝑐π‘₯𝑖,𝑐𝑦𝑖,𝑐𝑧𝑖,𝑦𝑖𝑧𝑖,𝑧𝑖𝑧𝑖+1,1 ≀ 𝑖 ≀ 𝑛}. The cardinality of vertex set is |𝑉(𝑆𝑓𝑛)| = 3𝑛 + 1 and the cardinality of edge set is |𝐸(𝑆𝑓𝑛)| = 5𝑛. Based on definition of sunflower graph, the graph 𝑆𝑓𝑛 has maximum degree of Ξ” (𝑆𝑓𝑛) = 3𝑛. To prove the rainbow antimagic connection number of 𝑆𝑓𝑛 , the first step is to determine the lower bound of π‘Ÿπ‘Žπ‘(𝑆𝑓𝑛). Based on Lemma 1. we have π‘Ÿπ‘Žπ‘(𝑆𝑓𝑛) β‰₯ Ξ”(𝑆𝑓𝑛). Since, the labels of the vertices with the bijection 𝑓:𝑉(𝑆𝑓𝑛) β†’ {1,2,…,|𝑉(𝑆𝑓𝑛)|}, we have On the study of Rainbow Antimagic Coloring of Special Graphs Dafik 591 𝑓(𝑒) β‰  𝑓(𝑣) for every vertex 𝑒,𝑣 ∈ 𝑉 (𝐺). It implies for each edge 𝑒π‘₯,𝑣π‘₯ ∈ 𝐸 (𝐺),𝑀 (𝑒π‘₯) β‰  𝑀 (𝑣π‘₯). Thus π‘Ÿπ‘Žπ‘ (𝑆𝑓𝑛) β‰₯ 3𝑛. The second step is to determine the upper bound of π‘Ÿπ‘Žπ‘(𝑆𝑓𝑛). Define the vertex labeling 𝑓 ∢ 𝑉(𝑆𝑓𝑛) β†’ {1,2, . . . ,3𝑛 + 1 } as follows. 𝑓(𝑐) = 1 𝑓(π‘₯𝑖) = 2𝑛 + 𝑖 + 1 , for 1 ≀ 𝑖 ≀ 𝑛 𝑓(𝑦𝑖) = 2𝑛 βˆ’ 𝑖 + 2 , for 1 ≀ 𝑖 ≀ 𝑛 𝑓(𝑧𝑖) = 𝑖 + 1 , for 1 ≀ 𝑖 ≀ 𝑛 The edge weight 𝑓 can be expressed as 𝑀(𝑐π‘₯𝑖) = 2𝑛 + 𝑖 + 2 , for 1 ≀ 𝑖 ≀ 𝑛 𝑀(𝑐𝑦𝑖) = 2𝑛 βˆ’ 𝑖 + 3 , for 1 ≀ 𝑖 ≀ 𝑛 𝑀(𝑐𝑧𝑖) = 𝑖 + 2 , for 1 ≀ 𝑖 ≀ 𝑛 𝑀(𝑦𝑖𝑧𝑖) = 2𝑛+3 , for 1 ≀ 𝑖 ≀ 𝑛 𝑀(𝑧𝑖𝑧𝑖+1) = { 2𝑖 + 3 , for 1 ≀ 𝑖 ≀ 𝑛 βˆ’ 1 𝑛 + 3 , for 𝑖 = 𝑛 The next step is to count the number of different edge weights inducing the rainbow antimagic coloring on the graph 𝑆𝑓𝑛. The edge weights are included in the sets 𝑀(𝑐π‘₯𝑖) βˆͺ 𝑀(𝑐𝑦𝑖) βˆͺ 𝑀(𝑐𝑧𝑖) = {3,4,5,…,3𝑛 + 2 },𝑀(𝑦𝑖𝑧𝑖) = {2𝑛 + 3} and 𝑀(𝑧𝑖𝑧𝑖+1) = {𝑛 + 3} βˆͺ {5,7,9,…2𝑛 + 1}. The number of distinct colors of 𝑀(𝑐π‘₯𝑖) βˆͺ 𝑀(𝑐𝑦𝑖) βˆͺ 𝑀(𝑐𝑧𝑖) βˆͺ 𝑀(𝑦𝑖𝑧𝑖) βˆͺ 𝑀(𝑧𝑖𝑧𝑖+1) is 3𝑛. Based on edge weights the number of edge wights is determined in the same way in Theorem 2. It implies that the edge weight 𝑓 ∢ 𝑉(𝑆𝑓𝑛) β†’ {1,2, . . . ,3𝑛 + 1} induces a rainbow antimagic coloring of 3𝑛 colors. Therefore π‘Ÿπ‘Žπ‘ (𝑆𝑓𝑛 ) ≀ 3𝑛. Combining two bounds, we have the exact value of π‘Ÿπ‘Žπ‘ (𝑆𝑓𝑛) = 3𝑛. The last is to show the existence of the rainbow π‘₯ βˆ’ 𝑦 path of 𝑆𝑓𝑛. According to the Theorem 1, since π‘‘π‘–π‘Žπ‘š(𝑆𝑓𝑛) = 2, for every two vertices of the π‘₯,𝑦 ∈ 𝑉(𝐺) there is a rainbow π‘₯ βˆ’ 𝑦 path. It completes the proof. The illustration of a rainbow antimagic coloring of sunflower graph 𝑆𝑓𝑛 can be seen in Figure 3. On the study of Rainbow Antimagic Coloring of Special Graphs Dafik 592 Figure 3. The illustration of rainbow antimagic coloring of sunflower graph 𝑆𝑓6. Theorem 5. For 𝑛 β‰₯ 3, π‘Ÿπ‘Žπ‘(𝑉𝑛) = 𝑛 + 2 . π‘ƒπ‘Ÿπ‘œπ‘œπ‘“. The volcano 𝑉𝑛 is a graph with vertex set 𝑉( 𝑉𝑛 ) = {π‘₯1,π‘₯2,π‘₯3} βˆͺ {𝑦𝑖,1 ≀ 𝑖 ≀ 𝑛} and edge set 𝐸(𝑉𝑛) = {π‘₯1π‘₯2,π‘₯2π‘₯3,π‘₯3π‘₯1} βˆͺ {π‘₯𝑖𝑦𝑖,1 ≀ 𝑖 ≀ 𝑛}. The cardinality of vertex set is |𝑉(𝑉𝑛)| = 𝑛 + 3 and the cardinality of edge set is |𝐸(𝑉𝑛)| = 𝑛 + 3. Based on definition of volcano graph, the graph 𝑉𝑛 has maximum degree of Ξ” (𝑉𝑛) = 𝑛 + 2. To prove the rainbow antimagic connection number of 𝑉𝑛 , the first step is to determine the lower bound of π‘Ÿπ‘Žπ‘(𝑉𝑛). Based on Lemma 1. we have π‘Ÿπ‘Žπ‘(𝑉𝑛) β‰₯ Ξ”(𝑉𝑛). Since, the labels of the vertices with the bijection 𝑓:𝑉(𝑉𝑛) β†’ {1,2,…, |𝑉(𝑉𝑛)|}, we have 𝑓(𝑒) β‰  𝑓(𝑣) for every vertex 𝑒,𝑣 ∈ 𝑉 (𝐺). It implies for each edge 𝑒π‘₯,𝑣π‘₯ ∈ 𝐸 (𝐺),𝑀 (𝑒π‘₯) β‰  𝑀 (𝑣π‘₯). Thus π‘Ÿπ‘Žπ‘ (𝑉𝑛) β‰₯ 𝑛 + 2. The second step is to determine the upper bound of π‘Ÿπ‘Žπ‘(𝑉𝑛). Define the vertex labeling 𝑓 ∢ 𝑉(𝑉𝑛) β†’ {1,2, . . . ,𝑛 + 3 } as follows. 𝑓(π‘₯1) = 1 𝑓(π‘₯2) = 2 𝑓(π‘₯3) = 3 𝑓(𝑦𝑖) = 𝑖 + 3 The edge weight 𝑓 can be expressed as 𝑀(π‘₯1π‘₯2) = 3 𝑀(π‘₯2π‘₯3) = 5 𝑀(π‘₯1π‘₯3) = 4 𝑀(π‘₯𝑖𝑦𝑖) = 𝑖 + 4 The next step is to count the number of different edge weights inducing the rainbow antimagic coloring on the graph 𝑉𝑛. The edge weights are included in the sets On the study of Rainbow Antimagic Coloring of Special Graphs Dafik 593 𝑀(π‘₯1π‘₯2) βˆͺ 𝑀(π‘₯2π‘₯3) βˆͺ 𝑀(π‘₯1π‘₯3) = {3,4,5 } and 𝑀(π‘₯𝑖𝑦𝑖) = {5,6,7,…,𝑛 + 4}. The number of distinct colors of 𝑀(π‘₯1π‘₯2) βˆͺ 𝑀(π‘₯2π‘₯3) βˆͺ 𝑀(π‘₯1π‘₯3) βˆͺ 𝑀(π‘₯𝑖𝑦𝑖) is 𝑛 + 2. Based on edge weights the number of edge wights is determined in the same way in Theorem 2. It implies that the edge weight 𝑓 ∢ 𝑉(𝑉𝑛) β†’ {1,2, . . . ,𝑛 + 3} induces a rainbow antimagic coloring of 𝑛 + 2 colors. Therefore π‘Ÿπ‘Žπ‘ (𝑉𝑛 ) ≀ 𝑛 + 2. Combining two bounds, we have the exact value of π‘Ÿπ‘Žπ‘ (𝑉𝑛) = 𝑛 + 2. The last is to show the existence of the rainbow π‘₯ βˆ’ 𝑦 path of 𝑉𝑛. According to the Theorem 1, since π‘‘π‘–π‘Žπ‘š(𝑉𝑛) = 2, for every two vertices of the π‘₯,𝑦 ∈ 𝑉(𝐺) there is a rainbow π‘₯ βˆ’ 𝑦 path. It completes the proof. The illustration of a rainbow antimagic coloring of volcano graph 𝑉𝑛 can be seen in Figure 4. Figure 4. The illustration of rainbow antimagic coloring of volcano graph 𝑉7. Theorem 6. For 𝑛 β‰₯ 3, π‘Ÿπ‘Žπ‘(𝑆𝐽𝑛) = 𝑛 . π‘ƒπ‘Ÿπ‘œπ‘œπ‘“. The semi jahangir graph 𝑆𝐽𝑛 is a graph with vertex set 𝑉( 𝑆𝐽𝑛 ) = {π‘Ž} βˆͺ { π‘₯𝑖,1 ≀ 𝑖 ≀ 𝑛} βˆͺ { 𝑦𝑖,1 ≀ 𝑖 ≀ 𝑛 βˆ’ 1} and edge set (𝑆𝐽𝑛) = {π‘Žπ‘₯𝑖,1 ≀ 𝑖 ≀ 𝑛} βˆͺ {π‘₯𝑖𝑦𝑖,𝑦𝑖π‘₯𝑖+1,1 ≀ 𝑖 ≀ 𝑛 βˆ’ 1}. The cardinality of vertex set is |𝑉(𝑆𝐽𝑛)| = 2𝑛 and the cardinality of edge set is |𝐸(𝑆𝐽𝑛)| = 3𝑛 βˆ’ 2. Based on definition of semi jahangir graph, the graph 𝑆𝐽𝑛 has maximum degree of Ξ” (𝑆𝐽𝑛) = 𝑛. To prove the rainbow antimagic connection number of 𝑆𝐽𝑛 , the first step is to determine the lower bound of π‘Ÿπ‘Žπ‘(𝑆𝐽𝑛). Based on Lemma 1. we have π‘Ÿπ‘Žπ‘(𝑆𝐽𝑛) β‰₯ Ξ”(𝑆𝐽𝑛). Since, the labels of the vertices with the bijection 𝑓:𝑉(𝑆𝐽𝑛) β†’ {1,2,…,|𝑉(𝑆𝐽𝑛)|}, we have 𝑓(𝑒) β‰  𝑓(𝑣) for every vertex 𝑒,𝑣 ∈ 𝑉 (𝐺). It implies for each edge 𝑒π‘₯,𝑣π‘₯ ∈ 𝐸 (𝐺),𝑀 (𝑒π‘₯) β‰  𝑀 (𝑣π‘₯). Thus π‘Ÿπ‘Žπ‘ (𝑆𝐽𝑛) β‰₯ 𝑛. The second step is to determine the upper bound of π‘Ÿπ‘Žπ‘(𝑆𝐽𝑛). Define the vertex labeling 𝑓 ∢ 𝑉(𝑆𝐽𝑛) β†’ {1,2, . . . ,2𝑛} as follows. 𝑓(π‘Ž) = { 𝑛 , for 𝑛 is odd 𝑛 + 1 , for 𝑛 is even 𝑓(π‘₯𝑖) = { 2 , for 𝑖 = 1 2𝑖 + 2 , for 2 ≀ 𝑖 ≀ 𝑛 βˆ’ 1 4 , for 𝑖 = 𝑛 𝑓(𝑦𝑖) = { 2𝑛 βˆ’ 2𝑖 + 1 , for 1 ≀ 𝑖 ≀ ⌈ 𝑛 2 βŒ‰ βˆ’ 1 2𝑛 βˆ’ 2𝑖 βˆ’ 3 , for ⌈ 𝑛 2 βŒ‰ ≀ 𝑖 ≀ 𝑛 βˆ’ 2 On the study of Rainbow Antimagic Coloring of Special Graphs Dafik 594 𝑓(π‘¦π‘›βˆ’1) = { 𝑖 βˆ’ 1 , for 𝑛 is odd 𝑖 , for 𝑛 is even The edge weight 𝑓 can be expressed as 𝑀(π‘Žπ‘₯𝑖) = { 𝑛 + 2 , for 𝑛 is odd 𝑛 + 3 , for 𝑛 is even 𝑀(π‘Žπ‘₯𝑖) = { 𝑛 + 2𝑖 + 2 , for 𝑛 is odd,2 ≀ 𝑖 ≀ 𝑛 βˆ’ 1 𝑛 + 2𝑖 + 3 , for 𝑛 is even,2 ≀ 𝑖 ≀ 𝑛 βˆ’ 1 𝑀(π‘Žπ‘₯𝑛) = { 𝑛 + 4 , for 𝑛 is odd 𝑛 + 5 , for 𝑛 is even 𝑀(π‘₯𝑖𝑦𝑖) = { 2𝑛 + 1 , for 𝑖 = 1 2𝑛 + 3 , for 2 ≀ 𝑖 ≀ ⌈ 𝑛 2 βŒ‰ βˆ’ 1 2𝑛 βˆ’ 1 , for ⌈ 𝑛 2 βŒ‰ ≀ 𝑖 ≀ 𝑛 βˆ’ 2 𝑀(π‘Žπ‘₯π‘›βˆ’1π‘¦π‘›βˆ’1) = { 3𝑛 βˆ’ 2 , for 𝑛 is odd 3𝑛 βˆ’ 1 , for 𝑛 is even 𝑀(𝑦𝑖π‘₯𝑖+1) = { 2𝑛 + 5 , for 2 ≀ 𝑖 ≀ ⌈ 𝑛 2 βŒ‰ βˆ’ 1 2𝑛 + 1 , for ⌈ 𝑛 2 βŒ‰ ≀ 𝑖 ≀ 𝑛 βˆ’ 2 2𝑛 βˆ’ 5 , for 𝑖 = 𝑛 βˆ’ 1 The next step is to count the number of different edge weights inducing the rainbow antimagic coloring on the graph 𝑆𝐽𝑛. The edge weights are included in the sets 𝑀(π‘₯𝑖𝑦𝑖) βˆͺ 𝑀(𝑦𝑖π‘₯𝑖+1) = {2𝑛 + 1,2𝑛 + 3,2𝑛 + 5 } and 𝑀(π‘Žπ‘₯𝑖) = {𝑛 + 3,𝑛 + 4,𝑛 + 5,…,3𝑛 + 1}. The number of distinct colors of 𝑀(π‘₯𝑖𝑦𝑖) βˆͺ 𝑀(𝑦𝑖π‘₯𝑖+1) βˆͺ 𝑀(π‘Žπ‘₯𝑖) is 𝑛. Based on edge weights the number of edge wights is determined in the same way in Theorem 2. It implies that the edge weight 𝑓 ∢ 𝑉(𝑆𝐽𝑛) β†’ {1,2, . . . ,3𝑛 βˆ’ 2} induces a rainbow antimagic coloring of 𝑛 colors. Therefore π‘Ÿπ‘Žπ‘ (𝑆𝐽𝑛 ) ≀ 𝑛. Combining two bounds, we have the exact value of π‘Ÿπ‘Žπ‘ (𝑆𝐽𝑛) = 𝑛. The last is to show the existence of the rainbow π‘₯ βˆ’ 𝑦 path of 𝑆𝐽𝑛. Suppose we take any π‘₯,𝑦 ∈ 𝑉(𝑆𝐽𝑛), there are two possibilities for π‘₯,𝑦, namely: π‘₯,𝑦 ∈ 𝑉(𝑆𝐽𝑛) where 𝑑(π‘₯,𝑦) ≀ 2 or π‘₯,𝑦 ∈ 𝑉(𝑆𝐽𝑛) where 𝑑(π‘₯,𝑦) β‰₯ 3. Suppose π‘₯,𝑦 ∈ 𝑉(𝑆𝐽𝑛) where 𝑑(π‘₯,𝑦) ≀ 2, based on Theorem 1, we must have the rainbow π‘₯ βˆ’ 𝑦 path. For π‘₯,𝑦 ∈ 𝑉(𝑆𝐽𝑛) where 𝑑(π‘₯,𝑦) β‰₯ 3, we have two case: First case for path π‘₯𝑖 βˆ’ 𝑦𝑗 we use the path π‘₯𝑖,π‘Ž,π‘₯𝑗,𝑦𝑗 or π‘₯𝑖,π‘Ž,π‘₯𝑗+1,𝑦𝑗. Second case for path 𝑦𝑖 βˆ’ 𝑦𝑗 we use the path 𝑦𝑖,π‘₯𝑖,π‘Ž,π‘₯𝑗,𝑦𝑗 or 𝑦𝑖,π‘₯𝑖,π‘Ž,π‘₯𝑗+1,𝑦𝑗 or 𝑦𝑖,π‘₯𝑖+1,π‘Ž,π‘₯𝑗,𝑦𝑗 or 𝑦𝑖,π‘₯𝑖+1,π‘Ž,π‘₯𝑗+1,𝑦𝑗. Thus, for π‘₯,𝑦 ∈ 𝑉(𝑆𝐽𝑛) there is a rainbow π‘₯ βˆ’ 𝑦 path. It completes the proof.The illustration of a rainbow antimagic coloring of semi jahangir graph 𝑆𝐽𝑛 can be seen in Figure 5. On the study of Rainbow Antimagic Coloring of Special Graphs Dafik 595 Figure 5. The illustration of rainbow antimagic coloring of semi jahangir graph 𝑆𝐽6. CONCLUDING REMARKS Based on these results, the authors get the results of the rainbow antimagic connection number on several graphs. The authors finds the exact value of the octopus graph 𝑂𝑛, sandat graph 𝑆𝑑𝑛, sunflower graph 𝑆𝑓𝑛, volcano graph 𝑉𝑛 and semi jahangir graph 𝑆𝐽𝑛. 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