On a distance-regular graph with an intersection array {35,28,6;1,2,30}

Автор: Makhnev Alexander A., Tokbaeva Albina A.

Журнал: Владикавказский математический журнал @vmj-ru

Статья в выпуске: 2 т.21, 2019 года.

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It is proved that for a distance-regular graph Γ of diameter 3 with eigenvalue θ2=-1 the complement graph of Γ3 is pseudo-geometric for pGc3(k,b1/c2). Bang and Koolen investigated distance-regular graphs with intersection arrays (t+1)s,ts,(s+1-ψ);1,2,(t+1)ψ. If t=4, s=7, ψ=6 then we have array 35,28,6;1,2,30. Distance-regular graph Γ with intersection array {35,28,6;1,2,30} has spectrum of 351, 9168, -1182, -5273, v=1+35+490+98=624 vertices and Γ3 is a pseudogeometric graph for pG30(35,14). Due to the border of Delsarte, the order of clicks in Γ is not more than 8. It is also proved that either a neighborhood of any vertex in Γ is the union of an isolated 7-click, or the neighborhood of any vertex in Γ does not contain a 7-click and is a connected graph. The structure of the group G of automorphisms of a graph Γ with an intersection array {35,28,6;1,2,30} has been studied. In particular, π(G)⊆{2,3,5,7,13} and the edge symmetric graph Γ has a solvable group automorphisms.

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Короткий адрес: https://sciup.org/143168796

IDR: 143168796   |   DOI: 10.23671/VNC.2019.2.32115

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