The graphs G(n,k) of the Johnson schemes are unique for n\(\geq 20\)
The Johnson graph J(n,k) has the k-subsets of a fixed n-set as vertices, adjacent iff they differ in just one element. J(n,k) is distance regular, and it is shown that for \(n\geq 20\) the intersection array of J(n,k) determines the graph. In the meantime it has been proved by \textit{P. Terwilliger} [Discrete Math., to appear] and the reviewer [Characterization of a class of distance regular graphs, J. Reine Angew. Math. 357, 182-192 (1985)] that the intersection array of J(n,k) determines the graph iff (n,k)\(\neq (8,2)\).
scientific article; zbMATH DE number 3887737
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