مشخصات پژوهش

Let $G_1=(V_1,E_1)$ and $G_2=(V_2,E_2)$ be two graphs with disjoint vertex sets $V_1$ and $V_2$. Let $u_1 \in V_1$ and $u_2 \in V_2$. The bridge graph of these two graphs with respect to $u_1$ and $u_2$ is the graph whose vertex set is $V_1 \cup V_2$ and edge set $E_1 \cup E_2 \cup \{e=u_1u_2\}$, where $e=u_1u_2$ is a new edge. In this paper we calculate the Szeged, edge-Szeged, $PI$, vertex-$PI$ and eccentric connectivity indices of bridge graphs.