Labelling of Generalized Friendship, Windmill, and Torch Graphs with a Condition at Distance Two
Ikhsanul Halikin, Hafif Komarullah ยท Advances in computer science research ยท 2022
A graph labelling with a condition at distance two was first introduced by Griggs and Robert.This labelling is also known as ๐ฟ(2,1)-labelling.Let ๐บ = (๐, ๐ธ) be a non-multiple graph, undirected, and connected.An ๐ฟ(2,1)-labelling on a graph is defined as a mapping from the vertex set ๐(๐บ) to the set of nonnegative integer such that for ๐ฅ, ๐ฆ โ ๐(๐บ), |๐(๐ฅ) -๐(๐ฆ)| โฅ 2 if ๐(๐ฅ, ๐ฆ) = 1 and |๐(๐ฅ) -๐(๐ฆ)| โฅ 1 if ๐(๐ฅ, ๐ฆ) = 2, where ๐(๐ฅ, ๐ฆ) denoted the distance between vertex ๐ฅ and ๐ฆ.The largest number of the vertex labels is called as span of ๐ฟ(2.1)-labelling.The span of a graph ๐บ can be more than one, the minimum value of the span of a graph ๐บ is notated by ๐ (2,1) (๐บ).In this paper, we consider a graph labelling with distance two on generalized friendship, windmill, and torch graphs. Keywords: ๐ฟ(2,1