Extremal spectral results of planar graphs without $C_{l,l}$ or $\mathrm{Theta}$ graph

HaoRan Zhang, WenHuan Wang

Let $\mathcal{F}$ be a given family of graphs. A graph $G$ is $\mathcal{F}$-free if it does not contain any member of $\mathcal{F}$ as a subgraph. Let $C_{l,l}$ be a graph obta…