21 citations · 30 across the 10 of their papers we have counts for
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math.CO2016
The integrally representable trees of norm 3
Jack H. Koolen, Masood Ur Rehman, Qianqian Yang
In this paper, we determine the integrally representable trees of norm 3.
math.CO2016
A generalization of a theorem of Hoffman
Jack H. Koolen, Qianqian Yang, Jae Young Yang
In 1977, Hoffman gave a characterization of graphs with smallest eigenvalue at least . In this paper we generalize this result to graphs with smaller smallest eigenvalue. For t…
math.CO2016
An application of Hoffman graphs for spectral characterizations of graphs
Qianqian Yang, Aida Abiad, Jack H. Koolen
In this paper, we present the first application of Hoffman graphs for spectral characterizations of graphs. In particular, we show that the -clique extension of the $(t+1)\times…