• Vishu Kumar M
• Soundarya R
• Hanumagowda B N

All sum graphs are disconnected in order for a connected graph to bear a sum labelling the graph is considered in conjuction with a number of isolated vertices , the labels of which complete the sum labeling for the disjoint union. The smallest number of isolated vertices required to make a graph is called sum number of G denoted by .An outer sum labelling is a labelling of graph G is an injective function with the property that for each vertex , there exist a vertex such that where N(v)={x:vx∈E(G)}. A graph G which admits an outer sum labeling is called an outer sum graph. If G is not an outer sum graph then minimum number of isolated verices required to make G a outer sum graph, is called outer sum number of G and is denoted by . In this paper we obtain outer sum number for some generalised friendship graph.

Sum labeling, Sum graph, Outer sum labeling, Outer sum graph, Friendship graph.

"OUTER SUM LABELING FOR FRIENDSHIP GRAPH", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.6, Issue 5, page no.200-204, May-2019, Available :http://www.jetir.org/papers/JETIR1905734.pdf

"OUTER SUM LABELING FOR FRIENDSHIP GRAPH", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.6, Issue 5, page no. pp200-204, May-2019, Available at : http://www.jetir.org/papers/JETIR1905734.pdf