Kaishun Wang

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A graph is s-regular if its automorphism group acts regularly on the set of its s-arcs. In this paper, we classify the s-regular elementary Abelian coverings of the three-dimensional hypercube for each s ≥ 1 whose fibre-preserving automorphism subgroups act arc-transitively. This gives a new infinite family of cubic 1-regular graphs, in which the smallest(More)
. (1) Let Fvq be a v-dimensional vector space over a finite field Fq. The q-Kneser graph qK(v, k) has as vertex set the collection of k-dimensional subspaces of F v q . Two vertices are adjacent if they intersect trivially. If k ≤ v < 2k, then qK(n, k) is null graph, so we only consider the case v ≥ 2k. Delsarte [1] calculated the eigenvalues of Grassmann(More)
We introduce some constructions of weakly distance-regular digraphs of girth 2, and prove that a certain quotient digraph of a commutative weakly distance-transitive digraph of girth 2 is a distancetransitive graph. As an application of the result, we obtain some examples of weakly distanceregular digraphs which are not weakly distance-transitive. Moreover,(More)