3 papers
math.CO2026
Signed graphs with fixed smallest eigenvalue at least and their lattices
Meng-Yue Cao, Jack H. Koolen, Jing-Yuan Liu +1
In this paper, we consider connected signed graphs with smallest eigenvalue at least for a small positive constant . We prove that if such a signed gr…
math.CO2026
A structure theory for signed graphs with fixed smallest eigenvalue
Jack H. Koolen, Jing-Yuan Liu, Qianqian Yang +1
In this paper, we will give a structure theory for signed graphs with fixed smallest eigenvalue and investigate signed graphs with smallest eigenvalue greater than . G…
math.CO2025
A Bose-Laskar-Hoffman theory for -bounded graphs with fixed smallest eigenvalue
Jack H. Koolen, Hong-Jun Ge, Chenhui Lv +1
In 2018, by Ramsey and Hoffman theory, Koolen, Yang, and Yang presented a structural result on graphs with smallest eigenvalue at least and large minimum degree. In this study…