ar X iv : 0 70 6 . 22 72 v 1 [ m at h . C O ] 1 5 Ju n 20 07 Expanders and the Affine Building of Sp n Alison Setyadi March 4 , 2008
نویسنده
چکیده
For n ≥ 2 and a local field K, let ∆n denote the affine building naturally associated to the symplectic group Spn(K). We compute the spectral radius of the subgraph Yn of ∆n induced by the special vertices in ∆n, from which it follows that Yn is an analogue of a family of expanders and is non-amenable.
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