المستخلص: |
In a connected graph 𝐺 = ( , 𝐸 ) , the distance from a vertex 𝑣 to a vertex 𝑢 , denoted 𝑑 ( 𝑢 , 𝑣 ) , is the length of the shortest path joins them. For a vertex 𝑣 in 𝐺 , the eccentricity 𝑒 ( 𝑣 ) is the distance to the farthest vertex from 𝑣 and for 0 ≤ 𝑘 ≤ 𝑒 ( 𝑣 ) , the 𝑘 -distance degree (𝑘 -degree) of 𝑣 , is 𝑑 𝑘 ( 𝑣 ) = { 𝑢 ∈ 𝑉 ( 𝐺 ) : 𝑑 ( 𝑣 , 𝑢 ) = 𝑘 } . The 𝑁 𝑘 -polynomial of a graph 𝐺 is a distance degree-based topological polynomial and is denoted by 𝑁 𝑘 ( , 𝑥 ) . It is a polynomial with the coefficient of the term , and is equal to the sum of 𝑑 𝑘 ( 𝑣 ) , for every 𝑣 ∈ 𝑉 ( 𝐺 ) . The roots of an 𝑁 𝑘 -polynomial of a graph are called the 𝑁 𝑘 -roots of 𝐺 and denoted by 𝑍 ( 𝑘 ( 𝐺 , 𝑥 ) ) . In this paper, we compute the 𝑁 𝑘 -polynomial of all graphs of order 𝑛 ≤ 6 , and present it in a table. The complement graph of every graph is found and presented directly in the same row of the table. Moreover, the roots 𝑍 ( 𝑘 ( 𝐺 , 𝑥 ) ) of every 𝑁 𝑘 -polynomial are estimated. The classes of graphs with the same 𝑁 𝑘 -polynomial are found. Finally, the relationship between the coefficients of 𝑁 𝑘 - polynomial and graph connectivity is presented.
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