A (2,1)-total labelling of a graph
,
is an assignment of integers to each vertex and
edge such that: (i) any two adjacent vertices of G receive distinct integers, (ii) any two adjacent edges of G
receive distinct integers, and (iii) a vertex and its incident edge receive integers that differ by at least 2. The
span of a (2,1)-total labelling is the maximum difference between two labels. The minimum span of a (2,1)-
total labelling of G is called the (2,1)-total number and denoted by
A cactus graph is a connected graph in which every block is either an edge or a cycle. In this paper, we label
that,
the vertices and edges of a cactus graph by
1
\uf044 \uf02b \uf0a3
