Connectivity concerning the last two subconstituents of a Q-polynomial distance-regular graph


Abstract in English

Let $Gamma$ be a $Q$-polynomial distance-regular graph of diameter $dgeq 3$. Fix a vertex $gamma$ of $Gamma$ and consider the subgraph induced on the union of the last two subconstituents of $Gamma$ with respect to $gamma$. We prove that this subgraph is connected.

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