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A graph related to Euler ϕ function

2020/12/23 by Ghanbari, Nima, Alikhani, Saeid
#05C05 #11AXX #Combinatorics (math.CO) #FOS: Mathematics

paper · doi:10.48550/arxiv.2012.12492

Abstract

Euler function ϕ(n) is the number of positive integers less than n and relatively prime to n. Suppose that ϕ1(n)=ϕ(n) and ϕi(n)=ϕ(ϕi-1(n)). Let A⊆ ℕ, and Aϕ=\ ϕk(n)| n∈ A , k∈ ℕ ∪ \0\\. We consider a graph Gϕ(A)=(V,E), where V=Aϕ and E=\\r,s\| r,s∈ V, ϕ(r)=s \. We say a graph H is a Gϕ-graph, if there exists a set of natural numbers A, such that H=Gϕ(A). In this paper we study the graph Gϕ(A) and investigate some specific graphs and some chemical trees as Gϕ-graph.

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