On the General Sum–Connectivity Co–Index of Graphs

Document Type: Research Paper


1 Beijing Institute of Technology, P. R. China

2 Changji University, P. R. China


In this paper, a new molecular-structure descriptor, the general sum–connectivity co–index   is considered, which generalizes the first Zagreb co–index and the general sum– connectivity index of graph theory. We mainly explore the lower and upper bounds in terms of the order and size for this new invariant. Additionally, the Nordhaus–Gaddum–type result is also represented.