The non-existence of some Moore polygons and spectral Moore bounds

Sebastian M. Cioabă, Vishal Gupta, Hiroshi Nozaki +1

In this paper, we study the maximum order $v(k,\hat{I}¸)$ of a connected $k$-regular graph whose second largest eigenvalue is at most $\hat{I}¸$. From Alon-Boppana and Serre, we know that $v(k…