On the Signed Complete Graphs with Maximum Index

Let $$\Gamma =(K_{n},H^-)$$ be a signed complete graph whose negative edges induce subgraph H. The index of $$\Gamma$$ is the largest eigenvalue its adjacency matrix. In this paper, we study when H unicyclic graph. We show that among all graphs order $$n>5$$ k and maximizes index, triangle with remaining vertices being pendant at same vertex triangle.