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On Additively Geometric Graphs

S. Arumugam1, K. A. Germina2, T.M.K. Anandavally3
1Core Group Research Facility (CGRF) National Centre for Advanced Research in Discrete Mathematics (n-CARDMATH) Kalasalingam University Anand Nagar,Krishnankoil-626 190. INDIA
2Department of Mathematics Mary Matha Arts and Science College Mananthavadi- 670645 Kerala, India.
3Department of Mathematics Payyanur College Payyanur-670327 Kerala, India.

Abstract

Let \( N \) and \( Z \) denote respectively the set of all nonnegative integers and the set of all integers. A \((p,q)\)-graph \( G = (V, E) \) is said to be additively \((a,r)\)-geometric if there exists an injective function \( f : V \to Z \) such that \( f^+(E) = \{a, ar, \dots, ar^{q-1}\} \) where \( a, r \in N \), \( r > 1 \), and \( f^+ \) is defined by \( f^+(uv) = f(u) + f(v) \) for all \( uv \in E \). If further \( f(v) \in N \) for all \( v \in V \), then \( G \) is said to be additively \((a,r)^*\)-geometric. In this paper we characterise graphs which are additively geometric and additively \(^*\)-geometric.

Keywords: Arithmetic graphs, geometric graphs, additively geometric graphs.