Characterizing the positive inertia index of connected signed graphs in terms of girth

Suliman Khan, Sakander Hayat, Mohammed J. F. Alenazi

Let $G^{\sigma }=(G,\sigma )$ be a connected signed graph and $A(G^{\sigma })$ be its adjacency matrix. The positive inertia index of $G^{\sigma }$, denoted by $p^{+}(G^{\sigma })$, is defined as the number of positive…