On a class of finite symmetric graphs

Let @C be a G-symmetric graph, and let B be a nontrivial G-invariant partition of the vertex set of @C. This paper aims to characterize (@C,G) under the conditions that the quotient graph @C"B is (G,2)-arc transitive and the induced subgraph between two adjacent blocks is 2@?K"2 or K"2","2. The results answer two questions about the relationship between @C and @C"B for this class of graphs.

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