186 citations · 238 across the 42 of their papers we have counts for
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math.CO2010★ 4 cited
The non-bipartite integral graphs with spectral radius three
Taeyoung Chung, Jack Koolen, Yoshio Sano +1
In this paper, we classify the connected non-bipartite integral graphs with spectral radius three.
math.CO2010★ 4 cited
Distance-regular graph with large a1 or c2
Jack H. Koolen, Jongyook Park
In this paper, we study distance-regular graphs that have a pair of distinct vertices, say x and y, such that the number of common neighbors of x and y is about half the valenc…
math.CO2010★ 2 cited
An inequality involving the second largest and smallest eigenvalue of a distance-regular graph
Jack H. Koolen, Jongyook Park, Hyonju Yu
For a distance-regular graph with second largest eigenvalue (resp. smallest eigenvalue) \mu1 (resp. \muD) we show that (\mu1+1)(\muD+1)<= -b1 holds, where equality only holds when…