Abstract
J.H. Koolen and J. Park found a boundary for the maximum size of the coclique in the neighborhood of a vertex of a distance-regular graph. Using this boundary, we prove that distance-regular graphs with the intersection arrays {83, 54, 21; 1, 6, 63}, {80, 54, 12; 1, 6, 60}, and {93, 64, 24; 1, 12, 62} do not exist.
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Funding
This work was financially supported by the Russian Foundation for Basic Research and the National Natural Science Foundation of China (project no. 20-51-53013), along with the National Natural Science Foundation of China (project no. 12171126).
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Translated by L. Kartvelishvili
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Makhnev, A.A., Guo, W. & Efimov, K.S. The Koolen–Park Boundary and Distance-Regular Graphs without m-Claws. Russ Math. 66, 54–57 (2022). https://doi.org/10.3103/S1066369X22090067
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DOI: https://doi.org/10.3103/S1066369X22090067