The maximum index of signed complete graphs whose negative edges induce a bicyclic graph

Ziyi Fang, Fan Chen, Xiying Yuan

Let $\Gamma =(K_n,H)$ be a signed complete graph whose negative edges induce a subgraph $H$. Let $A(\Gamma )$ be the adjacency matrix of the signed graph $\Gamma$. The largest eigenvalue of $A(\Gamma )$…