Total Neighbourhood Prime Labeling of Certain Graphs

In this paper, we investigate the total neighbourhood prime labelling of Lily graphs, Umbrella graph, Friendship graph F_n , Generalised friendship graph F{r}_n{}⁽⁴⁾,\bar{F}{r}_n{}⁽³⁾ and \bar{F}{r}_n{}⁽⁴⁾.