Abstract
Firstly, we prove that every closed subgroup H of type-preserving automorphisms of a locally finite thick affine building Δ of dimension ≥ 2 that acts strongly transitively on Δ is Moufang. If moreover Δ is irreducible and H is topologically simple, we show that H is the subgroup G(k) + of the k-rational points G(k) of the isotropic simple algebraic group G over a non-Archimedean local field k associated with Δ. Secondly, we generalise the proof given in Burger and Mozes (Inst. Hautes Études Sci. Publ. Math., 92, 151–194 (2001) 2000) for the case of bi-regular trees to any locally finite thick affine building Δ, and obtain that any topologically simple, closed, strongly transitive and type-preserving subgroup of Aut(Δ) has the Howe–Moore property. This proof is different than the strategy used so far in the literature and does not rely on the polar decomposition KA +K, where K is a maximal compact subgroup, and the important fact that A + is an abelian maximal sub-semi-group.
Originalsprog | Engelsk |
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Tidsskrift | Transformation Groups |
Vol/bind | 30 |
Nummer | 1 |
Sider (fra-til) | 165-185 |
Antal sider | 21 |
ISSN | 1083-4362 |
DOI | |
Status | Udgivet - mar. 2025 |